Umeå University's logo

umu.sePublications
Change search
Refine search result
12345 1 - 50 of 243
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Ahlinder, Jon
    et al.
    Division of CBRN Defence and Security, Swedish Defence Research Agency, Umeå, Sweden.
    Giles, Barbara
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    García-Gil, M. Rosario
    Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, Sweden.
    Life stage-specific inbreeding depression in long-lived Pinaceae species depends on population connectivity2021In: Scientific Reports, E-ISSN 2045-2322, Vol. 11, no 1, article id 8834Article in journal (Refereed)
    Abstract [en]

    Inbreeding depression (ID) is a fundamental selective pressure that shapes mating systems and population genetic structures in plants. Although it has been shown that ID varies over the life stages of shorter-lived plants, less is known about how the fitness effects of inbreeding vary across life stages in long-lived species. We conducted a literature survey in the Pinaceae, a tree family known to harbour some of the highest mutational loads ever reported. Using a meta-regression model, we investigated distributions of inbreeding depression over life stages, adjusting for effects of inbreeding levels and the genetic differentiation of populations within species. The final dataset contained 147 estimates of ID across life stages from 41 studies. 44 Fst estimates were collected from 40 peer-reviewed studies for the 18 species to aid genetic differentiation modelling. Partitioning species into fragmented and well-connected groups using Fst resulted in the best way (i.e. trade-off between high goodness-of-fit of the model to the data and reduced model complexity) to incorporate genetic connectivity in the meta-regression analysis. Inclusion of a life stage term and its interaction with the inbreeding coefficient (F) dramatically increased model precision. We observed that the correlation between ID and F was significant at the earliest life stage. Although partitioning of species populations into fragmented and well-connected groups explained little of the between-study heterogeneity, the inclusion of an interaction between life stage and population differentiation revealed that populations with fragmented distributions suffered lower inbreeding depression at early embryonic stages than species with well-connected populations. There was no evidence for increased ID in late life stages in well-connected populations, although ID tended to increase across life stages in the fragmented group. These findings suggest that life stage data should be included in inbreeding depression studies and that inbreeding needs to be managed over life stages in commercial populations of long-lived plants.

    Download full text (pdf)
    fulltext
  • 2.
    Ahnesjö, Ingrid
    et al.
    Department of Ecology and Genetics/Animal Ecology, Uppsala University, Uppsala, Sweden.
    Brealey, Jaelle C.
    Department of Ecology and Genetics/Animal Ecology, Uppsala University, Uppsala, Sweden.
    Günter, Katerina P.
    Centre for Gender Research, Uppsala University, Uppsala, Sweden.
    Martinossi‑Allibert, Ivain
    Department of Ecology and Genetics/Animal Ecology, Uppsala University, Uppsala, Sweden; Department of Organismal Biology/Systematic Biology, Uppsala University, Uppsala, Sweden.
    Morinay, Jennifer
    Department of Ecology and Genetics/Animal Ecology, Uppsala University, Uppsala, Sweden; Université de Lyon, France.
    Siljestam, Mattias
    Department of Ecology and Genetics/Animal Ecology, Uppsala University, Uppsala, Sweden.
    Stångberg, Josefine
    Department of Ecology and Genetics/Animal Ecology, Uppsala University, Uppsala, Sweden.
    Vasconcelos, Paula
    Department of Ecology and Genetics/Animal Ecology, Uppsala University, Uppsala, Sweden.
    Considering gender‑biased assumptions in evolutionary biology2020In: Evolutionary biology, ISSN 0071-3260, E-ISSN 1934-2845, Vol. 47, p. 1-5Article in journal (Refereed)
    Abstract [en]

    Many organisms studied by evolutionary biologists have different sexes, and the evolution of separate sexes and sexual dimorphisms in morphology and behaviour are central questions in evolutionary biology. Considering scientists to be embedded in a social and cultural context, we are also subjected to the risk of gender-biased assumptions and stereotypical thinking to appear when working on topics related to sexual reproduction and sexual dimorphism. Here we present, for continued discussion, a set of good-practice guidelines aimed at (1) helping to improve researchers’ awareness of gender-biased assumptions underlying language use, generalizations, and interpretation of observations; and (2) providing recommendations to increase transparency, avoid problematic terminology, and improve study designs.

    Download full text (pdf)
    fulltext
  • 3.
    Akhter, Shirin
    et al.
    Department of Plant Biology, Linnean Center for Plant Biology, Uppsala BioCentre, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden.
    Westrin, Karl Johan
    Science for Life Laboratory, Department of Gene Technology, KTH Royal Institute of Technology, Solna, Sweden.
    Zivi, Nathan
    Department of Plant Biology, Linnean Center for Plant Biology, Uppsala BioCentre, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden; Skogforsk, Uppsala Science Park, Uppsala, Sweden.
    Nordal, Veronika
    Department of Plant Biology, Linnean Center for Plant Biology, Uppsala BioCentre, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden.
    Kretzschmar, Warren W.
    Science for Life Laboratory, Department of Gene Technology, KTH Royal Institute of Technology, Solna, Sweden.
    Delhomme, Nicolas
    Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences (SLU), Umeå, Sweden.
    Street, Nathaniel R.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Nilsson, Ove
    Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences (SLU), Umeå, Sweden.
    Emanuelsson, Olof
    Science for Life Laboratory, Department of Gene Technology, KTH Royal Institute of Technology, Solna, Sweden.
    Sundström, Jens F.
    Department of Plant Biology, Linnean Center for Plant Biology, Uppsala BioCentre, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden.
    Cone-setting in spruce is regulated by conserved elements of the age-dependent flowering pathway2022In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 236, no 5, p. 1951-1963Article in journal (Refereed)
    Abstract [en]

    Reproductive phase change is well characterized in angiosperm model species, but less studied in gymnosperms. We utilize the early cone-setting acrocona mutant to study reproductive phase change in the conifer Picea abies (Norway spruce), a gymnosperm. The acrocona mutant frequently initiates cone-like structures, called transition shoots, in positions where wild-type P. abies always produces vegetative shoots.

    We collect acrocona and wild-type samples, and RNA-sequence their messenger RNA (mRNA) and microRNA (miRNA) fractions. We establish gene expression patterns and then use allele-specific transcript assembly to identify mutations in acrocona. We genotype a segregating population of inbred acrocona trees.

    A member of the SQUAMOSA BINDING PROTEIN-LIKE (SPL) gene family, PaSPL1, is active in reproductive meristems, whereas two putative negative regulators of PaSPL1, miRNA156 and the conifer specific miRNA529, are upregulated in vegetative and transition shoot meristems. We identify a mutation in a putative miRNA156/529 binding site of the acrocona PaSPL1 allele and show that the mutation renders the acrocona allele tolerant to these miRNAs. We show co-segregation between the early cone-setting phenotype and trees homozygous for the acrocona mutation.

    In conclusion, we demonstrate evolutionary conservation of the age-dependent flowering pathway and involvement of this pathway in regulating reproductive phase change in the conifer P. abies.

    Download full text (pdf)
    fulltext
  • 4. Alneberg, Johannes
    et al.
    Bennke, Christin
    Beier, Sara
    Bunse, Carina
    Quince, Christopher
    Ininbergs, Karolina
    Riemann, Lasse
    Ekman, Martin
    Jürgens, Klaus
    Labrenz, Matthias
    Pinhassi, Jarone
    Andersson, Anders F.
    Ecosystem-wide metagenomic binning enables prediction of ecological niches from genomes2020In: Communications Biology, E-ISSN 2399-3642, Vol. 3, no 1, article id 119Article in journal (Refereed)
    Abstract [en]

    The genome encodes the metabolic and functional capabilities of an organism and should be a major determinant of its ecological niche. Yet, it is unknown if the niche can be predicted directly from the genome. Here, we conduct metagenomic binning on 123 water samples spanning major environmental gradients of the Baltic Sea. The resulting 1961 metagenome-assembled genomes represent 352 species-level clusters that correspond to 1/3 of the metagenome sequences of the prokaryotic size-fraction. By using machine-learning, the placement of a genome cluster along various niche gradients (salinity level, depth, size-fraction) could be predicted based solely on its functional genes. The same approach predicted the genomes’ placement in a virtual niche-space that captures the highest variation in distribution patterns. The predictions generally outperformed those inferred from phylogenetic information. Our study demonstrates a strong link between genome and ecological niche and provides a conceptual framework for predictive ecology based on genomic data.

    Download full text (pdf)
    fulltext
  • 5.
    Andersson, Bea Angelica
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Analysis of Selection and Genetic Drift in a Dioecious Plant: Spatial Genetic Structure and Selection in Phenotypic Traits in a Young Island Population of Silene dioica2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Selection and genetic drift are often competing forces in shaping genetic structure in populations. Genetic drift will often effectively cancel out the effect of selection when population sizes are small, such as in colonizing island populations. On a small island in the Skeppsvik Archipelago in northern Sweden, a newly founded population of Silene dioica has been monitored since it first established around 1993. Though inhabiting an area of merely 173 m2, the population has been shown to exhibit a genetically differentiated patch structure where closely related individuals are tightly grouped, distanced from other family groups. In this study, the effect of selection was evaluated as compared to that of genetic drift. Variation in phenotypic traits in flowers, leaves and stalks were compared to that of neutral markers, in the form of PST and FST measures, to assess a measure of what proportion of differentiation among patches in phenotypic traits could not be attributed to genetic drift. Males and females were analysed separately to obtain measures of sex specific selection. Signs of divergent and stabilizing selection were found in several traits in both males and females despite the small spatial scale and short time since colonization. Further analysis is needed to assess explanations for trait divergence among patches and direction of selection.

    Download full text (pdf)
    fulltext
  • 6.
    Andersson, Bea Angelica
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Finding fitness: empirical and theoretical explorations of inferring fitness effects from population-level SNP data2024Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The distribution of fitness effects (DFE) describes the likelihood that a new mutation has a specific effect on the fitness of an individual in a given population. The shape of the DFE is a result of several factors such as population size, mating system and selective environment, and can in turn influence the evolutionary potential of a species. The DFE has long been a field of intense research, but particularly since molecular methods enabled us to study of genetic variation in organisms empirically. This research has led to the development of several statistical methods that use population-level frequencies of single nucleotide polymorphisms (SNPs) to infer the DFE. However, these methods rely on assumptions about the data and the organism itself, which could potentially affect the accuracy of the inferences. In this thesis, I describe how two major factors – data quality and inbreeding – can affect the accuracy of DFE inferences. I also show how and when to (and when not to) use DFE inference methods based on SNP frequencies.

    All genomic datasets contain inaccuracies and some level of uncertainty. The data sets are therefore often treated to remove the gaps or less reliable information, such as genotypes with low coverage. Some data sets need heavy filtering, which could reduce the amount of data available for analysis. We show that the choice of filter method affects the size of the final data set and the accuracy of the estimated DFE.

    Many DFE estimation software assumes random mating within the study population. Unfortunately, this assumption induces some error when trying to estimate the DFE in inbred or selfing species. Some have assumed that this is a result of high rates of homozygosity in the data, and should only be a problem in populations with very high rates of selfing (>99%). We show that accuracy of the estimated DFE decreases already at relatively low rates of selfing (70%) and that removing homozygosity does not improve the accuracy, implying that another mechanism could be causing the error.

    Download full text (pdf)
    fulltext
    Download (pdf)
    spikblad
    Download (png)
    presentationsbild
  • 7.
    Andersson, Bea
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Zhao, Wei
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Haller, Benjamin C.
    Department of Computational Biology, Cornell University, NY, Ithaca, United States.
    Brännström, Åke
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics. Advancing Systems Analysis Program, International Institute for Applied Systems Analysis, Laxenburg, Austria; Complexity Science and Evolution Unit, Okinawa Institute of Science and Technology Graduate University, Kunigami, Japan.
    Wang, Xiao-Ru
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Inference of the distribution of fitness effects of mutations is affected by single nucleotide polymorphism filtering methods, sample size and population structure2023In: Molecular Ecology Resources, ISSN 1755-098X, E-ISSN 1755-0998, Vol. 23, no 7, p. 1589-1603Article in journal (Refereed)
    Abstract [en]

    The distribution of fitness effects (DFE) of new mutations has been of interest to evolutionary biologists since the concept of mutations arose. Modern population genomic data enable us to quantify the DFE empirically, but few studies have examined how data processing, sample size and cryptic population structure might affect the accuracy of DFE inference. We used simulated and empirical data (from Arabidopsis lyrata) to show the effects of missing data filtering, sample size, number of single nucleotide polymorphisms (SNPs) and population structure on the accuracy and variance of DFE estimates. Our analyses focus on three filtering methods—downsampling, imputation and subsampling—with sample sizes of 4–100 individuals. We show that (1) the choice of missing-data treatment directly affects the estimated DFE, with downsampling performing better than imputation and subsampling; (2) the estimated DFE is less reliable in small samples (<8 individuals), and becomes unpredictable with too few SNPs (<5000, the sum of 0- and 4-fold SNPs); and (3) population structure may skew the inferred DFE towards more strongly deleterious mutations. We suggest that future studies should consider downsampling for small data sets, and use samples larger than 4 (ideally larger than 8) individuals, with more than 5000 SNPs in order to improve the robustness of DFE inference and enable comparative analyses.

    Download full text (pdf)
    fulltext
  • 8.
    Andersson, Bea
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Zhao, Wei
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Haller, Benjamin
    Department of Computational Biology Cornell University Ithaca New York USA.
    Wang, Xiao-Ru
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Brännström, Åke
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    Effects of self-fertilization on DFE inferenceManuscript (preprint) (Other academic)
  • 9.
    Andersson, Rebecka
    et al.
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    Isaksson, Hanna
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    Libby, Eric
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics. Santa Fe Institute, NM, Santa Fe, USA.
    Multi-species multicellular life cycles2022In: The evolution of multicellularity, CRC Press, 2022, p. 343-356Chapter in book (Refereed)
    Abstract [en]

    Textbook examples of multicellular organisms vary in their scale and complexity but are typically composed of a single species. The prevalence of entities such as lichens, however, suggest that two different species may be capable of forming a type of multi-species multicellularity-though it may not resemble its clonal counterparts. In this chapter, we consider the possibility of multi-species multicellularity and in particular its origins. Drawing upon previous studies of the evolutionary origins of clonal multicellularity, we focus on the emergence of simple reproducing groups that have the capacity to gain adaptations. We present a framework for organizing these initial multi-species group life cycles based on whether the constituent species are unicellular or multicellular and whether the groups reproduce via fragmentation or cycles of dissociation and re-association. We discuss characteristics of each type of multi-species multicellularity and representative examples to assess their likely evolutionary trajectories. Ultimately, we conclude that the multi-species groups that most resemble textbook multicellular organisms are composed of unicellular and multicellular species and reproduce via cycles of dissociation and re-association.

  • 10. Araki, N.H.T.
    et al.
    Khatab, I.A.
    Hemamali, K.K.G.U.
    Inomata,, N.
    Wang, Xiao-Ru
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Szmidt, A.E.
    Phylogeography of Larix sukaczewii Dyl. and Larix sibirica L. inferred from nucleotide variation of nuclear genes2008In: Tree Genetics & Genomes, ISSN 1614-2942, E-ISSN 1614-2950, Vol. 4, p. 611-623Article in journal (Refereed)
    Abstract [en]

    We investigated phylogeography of Larix sukaczewii and Larix sibirica using nucleotide variation at three following nuclear gene regions: 5.8 S rDNA including two internal transcribed spacers (ITS), cinnamyl alcohol dehydrogenase (CAD), and phytochrome-O (PHYO). We also included sequences of the 4-coumarate: coenzyme A ligase (4CL) gene region obtained in our recent study. CAD and PHYO showed very low nucleotide variation, but ITS and 4CL had levels of variation similar to those reported for other conifers. Pleistocene refugia have been hypothesized to exist in the Southern Urals and South Central Siberia, where four out of nine of the investigated populations occur. We found moderate to high levels of population differentiation (FST=0.115–0.531) in some pairwise comparisons suggesting limited gene flow and independent evolution of some refugial populations. In L. sukaczewii, low levels of differentiation were found among populations from areas glaciated during the Pleistocene, indicating their recent origin. Our results also suggest these populations were created by migrants from multiple, genetically distinct refugia. Furthermore, some haplotypes observed in populations from previously glaciated areas were not found in putative refugial populations, suggesting these populations might have contributed little to the extant populations created after the Last Glacial Maximum. Some authors regard L. sukaczewii and L. sibirica as a single species, while others consider them as separate species. The observed conspicuous differences in haplotype composition and distribution between L. sukaczewii and L. sibirica, together with high values of FST between populations of the two species, appear to support the latter classification.

  • 11. Backhouse, Amy
    et al.
    Sait, Steven M.
    Cameron, Tom C.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Multiple mating in the traumatically inseminating Warehouse pirate bug, Xylocoris flavipes: effects on fecundity and longevity2012In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 8, no 5, p. 706-709Article in journal (Refereed)
    Abstract [en]

    Optimal mating frequencies differ between sexes as a consequence of the sexual differentiation of reproductive costs per mating, where mating is normally more costly to females than males. In mating systems where sexual reproduction is costly to females, sexual conflict may cause both direct (i.e. by reducing female fecundity or causing mortality) and indirect (i.e. increased risk of mortality, reduced offspring viability) reductions in lifetime reproductive success of females, which have individual and population consequences. We investigated the direct and indirect costs of multiple mating in a traumatically inseminating (TI) predatory Warehouse pirate bug, Xylocoris flavipes (Reuter) (Hemiptera: Anthocoridae), where the male penetrates the female's abdomen during copulation. This study aimed to quantify the effects of TI on female fecundity, egg viability, the lifetime fecundity schedule, longevity and prey consumption in this cosmopolitan biocontrol agent. We found no difference in the total reproductive output between mating treatments in terms of total eggs laid or offspring viability, but there were significant differences found in daily fecundity schedules and adult longevity. In terms of lifetime reproduction, female Warehouse pirate bugs appear to be adapted to compensate for the costs of TI mating to their longevity.

  • 12.
    Bag, Pushan
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    How could Christmas trees remain evergreen?: photosynthetic acclimation of Scots pine and Norway spruce needles during winter2022Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Plants and other green organisms harvest sunlight by green chlorophyll pigments and covertit to chemical energy (sugars) and oxygen in a process called photosynthesis providing the foundation for life on Earth. Although it is unanimously believed that oceanic phytoplanktons are the main contributors to the global photosynthesis, the contribution of coniferous boreal forests distributed across vast regions of the northern hemisphere cannot be undermined. Hence boreal forests account signifificantly for social, economical and environmental sustainability. Not only do conifers thrive in the tundra regions with extreme climate, but they also maintain their needles green over the boreal winter. A question remains; what makes them so resilient? In this respect, we aimed to understand the remarkable winter adaptation strategies in two dominant boreal coniferous species,i.e., Pinus sylvestris and Picea abies. First, we mapped the transcriptional landscape in Norway spruce (Picea abies) needles over the annual cycle. Transcriptional changes in the nascent needles reflflected a sequence of developmental processes and active vegetative growth during early summer and summer. Later after maturation, transcriptome reflflected activated defense against biotic factors and acclimationin response to abiotic environmental cues such as freezing temperatures during winter. Secondly, by monitoring the photosynthetic performance of Scot pine needles, we found that the trees face extreme stress during the early spring (Feb-Mar) when sub-zero temperatures are accompanied by high solar radiation. At this time, drastic changes occur in the thylakoid membranes of the chloroplast that allows the mixing of photosystem I and photosystem II that typically remain laterally segregated. This triggers direct energy transfer from PSII to PSI and thus protects PSII from damage. Furthermore, we found that this loss of lateral segregation may be a consequence of triple phosphorylationof Lhcb1 (Light harvesting complex1 of photosystem II). The structural changes in thylakoid membranes also lead to changes inthe thylakoid macro domain organisationand pigment protein composition. Furthermore, we discovered that while PSII is protected by direct energy transfer, the protection of PSI is provided through photoreduction of oxygen by flavodiiron proteins, which in turn allows P700 to stay in an oxidised state necessary for direct energy transfer. These coordinated cascades of changes concomitantly protect both PSI and PSII to maintain the needles green over the winter.

    Download full text (pdf)
    fulltext
    Download (pdf)
    spikblad
    Download (jpg)
    presentationsbild
  • 13. Balint, Miklos
    et al.
    Pfenninger, Markus
    Grossart, Hans-Peter
    Taberlet, Pierre
    Vellend, Mark
    Leibold, Mathew A.
    Englund, Göran
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Bowler, Diana
    Environmental DNA time series in ecology2018In: Trends in Ecology & Evolution, ISSN 0169-5347, E-ISSN 1872-8383, Vol. 33, no 12, p. 945-957Article, review/survey (Refereed)
    Abstract [en]

    Ecological communities change in time and space, but long-term dynamics at the century-to-millennia scale are poorly documented due to lack of relevant data sets. Nevertheless, understanding long-term dynamics is important for explaining present-day biodiversity patterns and placing conservation goals in a historical context. Here, we use recent examples and new perspectives to highlight how environmental DNA (eDNA) is starting to provide a powerful new source of temporal data for research questions that have so far been overlooked, by helping to resolve the ecological dynamics of populations, communities, and ecosystems over hundreds to thousands of years. We give examples of hypotheses that may be addressed by temporal eDNA biodiversity data, discuss possible research directions, and outline related challenges.

  • 14. Belfield, Eric J.
    et al.
    Brown, Carly
    Ding, Zhong Jie
    Chapman, Lottie
    Luo, Mengqian
    Hinde, Eleanor
    van Es, Sam W.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Johnson, Sophie
    Ning, Youzheng
    Zheng, Shao Jian
    Mithani, Aziz
    Harberd, Nicholas P.
    Thermal stress accelerates Arabidopsis thaliana mutation rate2021In: Genome Research, ISSN 1088-9051, E-ISSN 1549-5469, Vol. 31, no 1, p. 40-50Article in journal (Refereed)
    Abstract [en]

    Mutations are the source of both genetic diversity and mutational load. However, the effects of increasing environmental temperature on plant mutation rates and relative impact on specific mutational classes (e.g., insertion /deletion [indel] vs. single nucleotide variant [SNV]) are unknown. This topic is important because of the poorly defined effects of anthropogen ic global temperature rise on biological systems. Here, we show the impact of temperature increase on Arabidopsis thaliana mutation, studying whole genome profiles of mutation accumulation (MA) lineages grown for 11 successive generations at 29 degrees C. Whereas growth of A. thaliana at standard temperature (ST; 23 degrees C) is associated with a mutation rate of 7 x10(-9) base substitutions per site per generation, growth at stressful high temperature (HT; 29 degrees C) is highly mutagenic, increasing the mutation rate to 12 x 10(-9). SNV frequency is approximately two- to threefold higher at HT than at ST, and HT-growth causes an similar to 19- to 23-fold increase in indel frequency, resulting in a disproportionate increase in indels (vs. SNVs). Most HT-induced indels are 1-2 bp in size and particularly affect homopolymeric or dinucleotide A or T stretch regions of the genome. HT-induced indels occur disproportionately in nucleosome-free regions, suggesting that much HT-induced mutational damage occurs during cell-cycle phases when genomic DNA is packaged into nucleosomes. We conclude that stressful experimental temperature increases accelerate plant mutation rates and particularly accelerate the rate of indel mutation. Increasing environmental temperatures are thus likely to have significant mutagenic consequences for plants growing in the wild and may, in particular, add detrimentally to mutational load.

  • 15. Berdahl, Andrew
    et al.
    Brelsford, Christa
    De Bacco, Caterina
    Dumas, Marion
    Ferdinand, Vanessa
    Grochow, Joshua A.
    Hebert-Dufresne, Laurent
    Kallus, Yoav
    Kempes, Christopher P.
    Kolchinsky, Artemy
    Larremore, Daniel B.
    Libby, Eric
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    Power, Eleanor A.
    Stern, Caitlin A.
    Tracey, Brendan D.
    Dynamics of beneficial epidemics2019In: Scientific Reports, E-ISSN 2045-2322, Vol. 9, article id 15093Article in journal (Refereed)
    Abstract [en]

    Pathogens can spread epidemically through populations. Beneficial contagions, such as viruses that enhance host survival or technological innovations that improve quality of life, also have the potential to spread epidemically. How do the dynamics of beneficial biological and social epidemics differ from those of detrimental epidemics? We investigate this question using a breadth-first modeling approach involving three distinct theoretical models. First, in the context of population genetics, we show that a horizontally-transmissible element that increases fitness, such as viral DNA, spreads superexponentially through a population, more quickly than a beneficial mutation. Second, in the context of behavioral epidemiology, we show that infections that cause increased connectivity lead to superexponential fixation in the population. Third, in the context of dynamic social networks, we find that preferences for increased global infection accelerate spread and produce superexponential fixation, but preferences for local assortativity halt epidemics by disconnecting the infected from the susceptible. We conclude that the dynamics of beneficial biological and social epidemics are characterized by the rapid spread of beneficial elements, which is facilitated in biological systems by horizontal transmission and in social systems by active spreading behavior of infected individuals.

    Download full text (pdf)
    fulltext
  • 16.
    Berggren, Hanna
    et al.
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM).
    Nordahl, Oscar
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM).
    Tibblin, Petter
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM).
    Larsson, Per
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM).
    Forsman, Anders
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM).
    Testing for local adaptation to spawning habitat in sympatric subpopulations of pike by reciprocal translocation of embryos2016In: PLOS ONE, E-ISSN 1932-6203, Vol. 11, no 5, article id e0154488Article in journal (Refereed)
    Abstract [en]

    We tested for local adaption in early life-history traits by performing a reciprocal translocation experiment with approximately 2,500 embryos of pike (Esox lucius) divided in paired split-family batches. The experiment indicated local adaptation in one of the two subpopulations manifested as enhanced hatching success of eggs in the native habitat, both when compared to siblings transferred to a non-native habitat, and when compared to immigrant genotypes from the other subpopulation. Gene-by-environment effects on viability of eggs and larvae were evident in both subpopulations, showing that there existed genetic variation allowing for evolutionary responses to divergent selection, and indicating a capacity for plastic responses to environmental change. Next, we tested for differences in female life-history traits. Results uncovered that females from one population invested more resources into reproduction and also produced more (but smaller) eggs in relation to their body size compared to females from the other population. We suggest that these females have adjusted their reproductive strategies as a counter-adaptation because a high amount of sedimentation on the eggs in that subpopulations spawning habitat might benefit smaller eggs. Collectively, our findings point to adaptive divergence among sympatric subpopulations that are physically separated only for a short period during reproduction and early development-which is rare. These results illustrate how combinations of translocation experiments and field studies of life-history traits might infer about local adaptation and evolutionary divergence among populations. Local adaptations in subdivided populations are important to consider in management and conservation of biodiversity, because they may otherwise be negatively affected by harvesting, supplementation, and reintroduction efforts targeted at endangered populations.

    Download full text (pdf)
    fulltext
  • 17.
    Berner, Daniel
    et al.
    Basel, Switzerland.
    Thibert-Plante, Xavier
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Knoxville, TN, USA; Uppsala, Sweden.
    How mechanisms of habitat preference evolve and promote divergence with gene flow2015In: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 28, no 9, p. 1641-1655Article in journal (Refereed)
    Abstract [en]

    Habitat preference may promote adaptive divergence and speciation, yet the conditions under which this is likely are insufficiently explored. We use individual-based simulations to study the evolution and consequence of habitat preference during divergence with gene flow, considering four different underlying genetically based behavioural mechanisms: natal habitat imprinting, phenotype-dependent, competition-dependent and direct genetic habitat preference. We find that the evolution of habitat preference generally requires initially high dispersal, is facilitated by asymmetry in population sizes between habitats, and is hindered by an increasing number of underlying genetic loci. Moreover, the probability of habitat preference to emerge and promote divergence differs greatly among the underlying mechanisms. Natal habitat imprinting evolves most easily and can allow full divergence in parameter ranges where no divergence is possible in the absence of habitat preference. The reason is that imprinting represents a one-allele mechanism of assortative mating linking dispersal behaviour very effectively to local selection. At the other extreme, direct genetic habitat preference, a two-allele mechanism, evolves under restricted conditions only, and even then facilitates divergence weakly. Overall, our results indicate that habitat preference can be a strong reproductive barrier promoting divergence with gene flow, but that this is highly contingent on the underlying preference mechanism.

  • 18.
    Bernhardsson, Carolina
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Molecular population genetics of inducible defense genes in Populus tremula2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Plant-herbivore interactions are among the most common of ecological interactions. It is therefore not surprising that plants have evolved multiple mechanisms to defend themselves, using both constitutive chemical and physical barriers and by induced responses which are only expressed after herbivory has occurred. Herbivores, on the other hand, respond to these plant defenses by evolving counter-adaptations which makes defenses less effective or even useless. Adaptation can occur at different geographical scales, with varying coevolutionary interactions across a spatially heterogenous landscape. By looking at the underlying genes responsible for these defensive traits and herbivore related phenotypic traits, it is possible to investigate the coevolutionary history of these plant- herbivore interactions. Here I use molecular population genetic tools to investigate the evolutionary history of several inducible defense genes in European Aspen (Populus tremula) in Sweden. Two genes, belonging to the Polyphenol oxidase gene-family (PPO1 and PPO2), show skews in their site frequency spectrum together with patterns of diversity and divergence from an outgroup which correspond to signatures of adaptive evolution (Paper II). 71 single nucleotide polymorphisms (SNPs) from seven inducible defense genes (PPO1-PPO3, TI2-TI5) show elevated levels of population differentiation compared to control genes (genes not involved in plant defense), and 10 of these defense SNPs show strong signatures of natural selection (Paper III). These 71 defense SNPs also divides a sample of Swedish P. tremula trees into three distinct geographical groups, corresponding to a Southern, Central and Northern cluster, a patterns that is not present in control SNPs (Paper III). The same geographical pattern, with a distinct Northern cluster, is also observed in several phenotypic traits related to herbivory in our common garden in Sävar (Paper IV). These phenotypic traits show patterns of apparent local maladaptation of the herbivore community to the host population which could indicate the presence of “information coevolution” between plants and herbivores (Paper IV). 15 unique defense SNPs also show significant associations to eight phenotypic traits but the causal effects of these SNP associations may be confounded by the geographic structure found in both the underlying genes and in the phenotypic traits. The co-occurrence of population structure in both defense genes and herbivore community traits may be the result from historical events during the post-glacial recolonization of Sweden.

    Download full text (pdf)
    Molecular population genetics of inducible defense genes in Populus tremula
    Download (pdf)
    Spikblad C. Bernhardsson
    Download (pdf)
    Omslag C. Bernhardsson
  • 19.
    Bernhardsson, Carolina
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Ingvarsson, Pär
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Geographic structure and adaptive population differentiation in herbivore defence genes in European aspen (Populus tremula L., Salicaceae)2012In: Molecular Ecology, ISSN 0962-1083, E-ISSN 1365-294X, Vol. 21, no 9, p. 2197-2207Article in journal (Refereed)
    Abstract [en]

    When a phenotypic trait is subjected to spatially variable selection and local adaptation, the underlying genes controlling the trait are also expected to show strong patterns of genetic differentiation since alternative alleles are favored in different geographical locations. Here we study 71 SNPs from seven genes associated with inducible defense responses in a sample of P. tremula collected from across Sweden. Four of these genes (PPO2, TI2, TI4 and TI5) show substantial population differentiation and a PCA conducted on the defense SNPs divides the Swedish population into three distinct clusters. Several defense SNPs show latitudinal clines, although these were not robust to multiple testing. However, five SNPs (located within TI4 and TI5) show strong longitudinal clines that remain significant after multiple test correction. Genetic geographical variation, supporting local adaptation, has earlier been confirmed in genes involved in the photoperiod pathway in P. tremula, but this is, to our knowledge, one of the first times that geographic variation has been found in genes involved in plant defense against antagonists.

  • 20.
    Bernhardsson, Carolina
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Robinson, Kathryn M.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Abreu, Ilka N.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Jansson, Stefan
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Ingvarsson, Pär K.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Albrectsen, Benedicte R.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Population differentiation in arthropod community structure and phenotypic association with inducible defense genes in European Aspen (Populus tremula L., salicaceae)Manuscript (preprint) (Other academic)
    Abstract [en]

    Plant-herbivore interactions are known to vary across a landscape due to both variation in abiotic and biotic factors. Such spatial variation tends to promoting local adaption of plants to the prevailing herbivore regime. Here we use data from a common garden to look for patterns across populations in the abundance and diversity of herbivorous insects. We also screen for variation in the untargeted metabolome of the foliage of a subset of the same trees. We also search for phenotypic associations between genetic variation in a number of wound-induced genes and phenotypic variation in herbivore abundance, diversity and in metabolomes. We observe significant genetic variation in a number of herbivore-related traits but low correlations between traits. We do observe substantial genetic structure in both herbivore community structure and in metabolic profiles and this structure is aligned with genetic structure we have previously documented for a set of defense genes. We also identify a number of significant associations between SNPs from wound-induced defense genes and a number of the herbivore traits and metabolic profiles. However, these associations are likely not causal, but are rather caused by the underlying population structure we observe. These results highlight to the importance of historical processes and the need to better understand both the current-day geographic distribution of different herbivore species as well as the post-glacial colonization history of both plants and herbivores.

  • 21.
    Bernhardsson, Carolina
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Department of Plant Biology, Linnean Centre for Plant Biology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Wang, Xi
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Department of Plant Biology, Linnean Centre for Plant Biology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Eklöf, Helena
    Department of Plant Biology, Linnean Centre for Plant Biology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Ingvarsson, Pär K.
    Department of Plant Biology, Linnean Centre for Plant Biology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Variant Calling Using Whole Genome Resequencing and Sequence Capture for Population and Evolutionary Genomic Inferences in Norway Spruce (Picea Abies)2020In: The Spruce Genome / [ed] Ilga M. Porth, Amanda R. De la Torre, Switzerland: Springer Nature, 2020, p. 9-36Chapter in book (Refereed)
    Abstract [en]

    Advances in next-generation sequencing methods and the development of new statistical and computational methods have opened up possibilities for large-scale, high-quality genotyping in most organisms. Conifer genomes are large and are known to contain a high fraction of repetitive elements and this complex genome structure has bearings for approaches that aim to use next-generation sequencing methods for genotyping. In this chapter, we provide a detailed description of a workflow for variant calling using next-generation sequencing in Norway spruce (Picea abies). The workflow starts with raw sequencing reads and proceeds through read mapping to variant calling and variant filtering. We illustrate the pipeline using data derived from both whole-genome resequencing data and reduced representation sequencing. We highlight possible problems and pitfalls of using next-generation sequencing data for genotyping stemming from the complex genome structure of conifers and how those issues can be mitigated or eliminated.

  • 22.
    Bernhardsson, Carolina
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Department of Organismal Biology, Uppsala University, Uppsala, Sweden.
    Zan, Yanjun
    Chen, Zhiqiang
    Ingvarsson, Pär K.
    Wu, Harry X.
    Development of a highly efficient 50K single nucleotide polymorphism genotyping array for the large and complex genome of Norway spruce (Picea abies L. Karst) by whole genome resequencing and its transferability to other spruce species2021In: Molecular Ecology Resources, ISSN 1755-098X, E-ISSN 1755-0998, Vol. 21, no 3, p. 880-896Article in journal (Refereed)
    Abstract [en]

    Norway spruce (Picea abies L. Karst) is one of the most important forest tree species with significant economic and ecological impact in Europe. For decades, genomic and genetic studies on Norway spruce have been challenging due to the large and repetitive genome (19.6 Gb with more than 70% being repetitive). To accelerate genomic studies, including population genetics, genome-wide association studies (GWAS) and genomic selection (GS), in Norway spruce and related species, we here report on the design and performance of a 50K single nucleotide polymorphism (SNP) genotyping array for Norway spruce. The array is developed based on whole genome resequencing (WGS), making it the first WGS-based SNP array in any conifer species so far. After identifying SNPs using genome resequencing data from 29 trees collected in northern Europe, we adopted a two-step approach to design the array. First, we built a 450K screening array and used this to genotype a population of 480 trees sampled from both natural and breeding populations across the Norway spruce distribution range. These samples were then used to select high-confidence probes that were put on the final 50K array. The SNPs selected are distributed over 45,552 scaffolds from the P. abies version 1.0 genome assembly and target 19,954 unique gene models with an even coverage of the 12 linkage groups in Norway spruce. We show that the array has a 99.5% probe specificity, >98% Mendelian allelic inheritance concordance, an average sample call rate of 96.30% and an SNP call rate of 98.90% in family trios and haploid tissues. We also observed that 23,797 probes (50%) could be identified with high confidence in three other spruce species (white spruce [Picea glauca], black spruce [P. mariana] and Sitka spruce [P. sitchensis]). The high-quality genotyping array will be a valuable resource for genetic and genomic studies in Norway spruce as well as in other conifer species of the same genus.

    Download full text (pdf)
    fulltext
  • 23.
    Bokma, Folmer
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Evolution as a Largely Autonomous Process2015In: Macroevolution: Explanation, Interpretation and Evidence / [ed] Emanuele Serrelli och Nathalie Gontier, Cham: Springer, 2015, p. 87-112Chapter in book (Refereed)
    Abstract [en]

    Evolutionary theory has proven generally successful in predicting phenotypic changes over one or a few generations of natural or artificial selection, but fails to predict evolutionary dynamics over longer periods of time, which is a major shortcoming: At longer timescales, existing theory is largely concerned with a posteriori explanations and cannot even predict whether a population or species will adapt to environmental change, or go extinct. Based on a review of key literature from before Darwin to today, I argue that the reason for this shortcoming is that in the Modern Synthesis fitness is regarded as determined exclusively by how well traits are suited to the biotic and abiotic environment. I argue that much can be gained by explicitly considering that fitness has a significant intrinsic component, determined by how well different traits are adapted to each other. Due to adaptation of traits to each other, those traits that are important for the functioning of many other traits can vary only within narrow tolerance limits. Short-term selection experiments and year-to-year fluctuations in natural populations taking place within these tolerance limits give the appearance of rapid evolution. Yet the tolerance limits will prevent changes to accumulate over time, and hence, these traits evolve in a million years no more than they do in a decade. Only traits like coloration that have little influence on other traits can evolve freely, but that will rarely be sufficient to prevent extinction. Significant evolutionary departures require a reshuffling of the interactions between traits and will often coincide with speciation. Emerging from a complex system of interacting traits, the magnitude and direction of these changes will be largely independent of the factors that triggered them, rendering macroevolution a largely autonomous process.

  • 24.
    Bokma, Folmer
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Baek, Seung Ki
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Minnhagen, Petter
    Umeå University, Faculty of Science and Technology, Department of Physics.
    50 years of inordinate fondness2014In: Systematic Biology, ISSN 1063-5157, E-ISSN 1076-836X, Vol. 63, no 2, p. 251-256Article in journal (Refereed)
  • 25.
    Bokma, Folmer
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Godinot, Marc
    Maridet, Olivier
    Ladeveze, Sandrine
    Costeur, Loic
    Sole, Floreal
    Gheerbrant, Emmanuel
    Peigne, Stephane
    Jacques, Florian
    Laurin, Michel
    Testing for Deperet's Rule (Body Size Increase) in Mammals using Combined Extinct and Extant Data2016In: Systematic Biology, ISSN 1063-5157, E-ISSN 1076-836X, Vol. 65, no 1, p. 98-108Article in journal (Refereed)
    Abstract [en]

    Whether or not evolutionary lineages in general show a tendency to increase in body size has often been discussed. This tendency has been dubbed "Cope's rule" but because Cope never hypothesized it, we suggest renaming it after Deperet, who formulated it clearly in 1907. Deperet's rule has traditionally been studied using fossil data, but more recently a number of studies have used present-day species. While several paleontological studies of Cenozoic placental mammals have found support for increasing body size, most studies of extant placentals have failed to detect such a trend. Here, we present a method to combine information from present-day species with fossil data in a Bayesian phylogenetic framework. We apply the method to body mass estimates of a large number of extant and extinct mammal species, and find strong support for Deperet's rule. The tendency for size increase appears to be driven not by evolution toward larger size in established species, but by processes related to the emergence of new species. Our analysis shows that complementary data from extant and extinct species can greatly improve inference of macroevolutionary processes.

    Download full text (pdf)
    fulltext
  • 26.
    Bokma, Folmer
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    van den Brink, Valentijn
    Stadler, Tanja
    Unexpectedly many extinct hominins2012In: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 66, no 9, p. 2969-2974Article in journal (Refereed)
    Abstract [en]

    Recent studies indicate that Neanderthal and Denisova hominins may have been separate species, while debate continues on the status of Homo floresiensis. The decade-long debate between splitters, who recognize over 20 hominin species, and lumpers, who maintain that all these fossils belong to just a few lineages, illustrates that we do not know how many extinct hominin species to expect. Here, we present probability distributions for the number of speciation events and the number of contemporary species along a branch of a phylogeny. With estimates of hominin speciation and extincton rates, we then show that the expected total number of extinct hominin species is 8, but may be as high as 27. We also show that it is highly unlikely that three very recent species disappeared due to natural, background extinction. This may indicate that human-like remains are too easily considered distinct species. Otherwise, the evidence suggesting that Neanderthal and the Denisova hominin represent distinct species implies a recent wave of extinctions, ostensibly driven by the only survivor, H. sapiens.

  • 27. Bourque, S.
    et al.
    Jeandroz, S.
    Grandperret, V.
    Lehotai, Nora
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Agroécologie, AgroSup Dijon, Centre National de la Recherche Scientifique (CNRS), Institut National de la Recherche Agronomique (INRA), Université Bourgogne Franche-Comté, Dijon, France.
    Aime, S.
    Soltis, D. E.
    Miles, N. W.
    Melkonian, M.
    Deyholos, M. K.
    Leebens-Mack, J. H.
    Chase, M. W.
    Rothfels, C. J.
    Stevenson, D. W.
    Graham, S. W.
    Wang, X.
    Wu, S.
    Pires, J. C.
    Edger, P. P.
    Yan, Z.
    Xie, Y.
    Carpenter, E. J.
    Wong, G. K. S.
    Wendehenne, D.
    Nicolas-Frances, V.
    The Evolution of HD2 Proteins in Green Plants2016In: Trends in Plant Science, ISSN 1360-1385, E-ISSN 1878-4372, Vol. 21, no 12, p. 1008-1016Article, review/survey (Refereed)
    Abstract [en]

    In eukaryotes, protein deacetylation is carried out by two well-conserved his tone deacetylase (HDAC) families: RPD3/HDA1 and SIR2. Intriguingly, model plants such as Arabidopsis express an additional plant-specific HDAC family, termed type-2 HDACs (HD2s). Transcriptomic analyses from more than 1300 green plants generated by the 1000 plants (1KP) consortium showed that HD2s appeared early in green plant evolution, the first members being detected in several streptophyte green alga. The HD2 family has expanded via several rounds of successive duplication; members are expressed in all major green plant clades. Interestingly, angiosperm species express new HD2 genes devoid of a zinc-finger domain, one of the main structural features of HD2s. These variants may have been associated with the origin and/or the biology of the ovule/seed.

  • 28.
    Bozdag, G. Ozan
    et al.
    School of Biological Sciences, Georgia Institute of Technology, GA, Atlanta, United States.
    Libby, Eric
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics. Santa Fe Institute, NM, Santa Fe, United States.
    Pineau, Rozenn
    School of Biological Sciences, Georgia Institute of Technology, GA, Atlanta, United States; Interdisciplinary Graduate Program in Quantitative Biosciences, Georgia Institute of Technology, GA, United States.
    Reinhard, Christopher T.
    School of Earth and Atmospheric Sciences, Georgia Institute of Technology, GA, Atlanta, United States; NASA Astrobiology Institute, Alternative Earths Team, CA, Riverside, United States.
    Ratcliff, William C.
    School of Biological Sciences, Georgia Institute of Technology, GA, Atlanta, United States; NASA Astrobiology Institute, Reliving the Past Team, GA, Atlanta, United States.
    Oxygen suppression of macroscopic multicellularity2021In: Nature Communications, E-ISSN 2041-1723, Vol. 12, no 1, article id 2838Article in journal (Refereed)
    Abstract [en]

    Atmospheric oxygen is thought to have played a vital role in the evolution of large, complex multicellular organisms. Challenging the prevailing theory, we show that the transition from an anaerobic to an aerobic world can strongly suppress the evolution of macroscopic multicellularity. Here we select for increased size in multicellular ‘snowflake’ yeast across a range of metabolically-available O2 levels. While yeast under anaerobic and high-O2 conditions evolved to be considerably larger, intermediate O2 constrained the evolution of large size. Through sequencing and synthetic strain construction, we confirm that this is due to O2-mediated divergent selection acting on organism size. We show via mathematical modeling that our results stem from nearly universal evolutionary and biophysical trade-offs, and thus should apply broadly. These results highlight the fact that oxygen is a double-edged sword: while it provides significant metabolic advantages, selection for efficient use of this resource may paradoxically suppress the evolution of macroscopic multicellular organisms.

    Download full text (pdf)
    fulltext
  • 29.
    Brännström, Åke
    et al.
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    Johansson, Jacob
    Lund University.
    von Festenberg, Niels
    The Hitchhiker’s Guide to Adaptive Dynamics2013In: Games, E-ISSN 2073-4336, no 4, p. 304-328Article in journal (Refereed)
    Abstract [en]

    Adaptive dynamics is a mathematical framework for studying evolution. It extends evolutionary game theory to account for more realistic ecological dynamics and it can incorporate both frequency- and density-dependent selection. This is a practical guide to adaptive dynamics that aims to illustrate how the methodology can be applied to the study of specific systems. The theory is presented in detail for a single, monomorphic, asexually reproducing population. We explain the necessary terminology to understand the basic arguments in models based on adaptive dynamics, including invasion fitness, the selection gradient, pairwise invasibility plots (PIP), evolutionarily singular strategies, and the canonical equation. The presentation is supported with a worked-out example of evolution of arrival times in migratory birds. We show how the adaptive dynamics methodology can be extended to study evolution in polymorphic populations using trait evolution plots (TEPs). We give an overview of literature that generalises adaptive dynamics techniques to other scenarios, such as sexual, diploid populations, and spatially-structured populations. We conclude by discussing how adaptive dynamics relates to evolutionary game theory and how adaptive-dynamics techniques can be used in speciation research.

    Download full text (pdf)
    fulltext
  • 30.
    Burdon, Jeremy J.
    et al.
    CSIRO-Plant Industry, Canberra, Australia.
    Thrall, Peter H.
    CSIRO-Plant Industry, Canberra, Australia.
    Ericson, Lars
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    The current and future dynamics of disease in plant communities2006In: Annual Review of Phytopathology, ISSN 0066-4286, E-ISSN 1545-2107, Vol. 44, p. 19-39Article in journal (Refereed)
    Abstract [en]

    Pathogens are powerful evolutionary forces shaping the structure and dynamics of both individual species and of the communities of which they are part, at a broad range of genetic, ecological, spatial, and temporal scales. At all these levels their impact varies from the subtle and little recognized through to the most obvious destruction. Today the direct role of pathogens in natural plant communities is better recognized than at previous times, although the nuances of their interactions and the cascade of ramifications that can flow through changing biotic and abiotic effects are only now gaining recognition. However, as human influence on pathogens increases either directly through enhanced if accidental dispersal, or through anthropogenic impacts on climate-we may expect to see increasing evidence of pathogens affecting plant species, community structure, and ecosystem function.

  • 31.
    Calatayud, Joaquín
    et al.
    Umeå University, Faculty of Science and Technology, Department of Physics. Departamento de Biogeografía y Cambio Global, Museo Nacional de Ciencias Naturales, Madrid, Spain.
    Andivia, Enrique
    Escudero, Adrian
    Melian, Carlos J.
    Bernardo-Madrid, Ruben
    Stoffel, Markus
    Aponte, Cristina
    Medina, Nagore G.
    Molina-Venegas, Rafael
    Arnan, Xavier
    Rosvall, Martin
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Neuman, Magnus
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Ari Noriega, Jorge
    Alves-Martins, Fernanda
    Draper, Isabel
    Luzuriaga, Arantzazu
    Ballesteros-Canovas, Juan Antonio
    Morales-Molino, Cesar
    Ferrandis, Pablo
    Herrero, Asier
    Pataro, Luciano
    Juen, Leandro
    Cea, Alex
    Madrigal-Gonzalez, Jaime
    Positive associations among rare species and their persistence in ecological assemblages2020In: Nature Ecology & Evolution, E-ISSN 2397-334X, Vol. 4, no 1, p. 40-45Article in journal (Refereed)
    Abstract [en]

    According to the competitive exclusion principle, species with low competitive abilities should be excluded by more efficient competitors; yet, they generally remain as rare species. Here, we describe the positive and negative spatial association networks of 326 disparate assemblages, showing a general organization pattern that simultaneously supports the primacy of competition and the persistence of rare species. Abundant species monopolize negative associations in about 90% of the assemblages. On the other hand, rare species are mostly involved in positive associations, forming small network modules. Simulations suggest that positive interactions among rare species and microhabitat preferences are the most probable mechanisms underpinning this pattern and rare species persistence. The consistent results across taxa and geography suggest a general explanation for the maintenance of biodiversity in competitive environments. Analysing spatial association networks among >300 terrestrial and aquatic assemblages, the authors find that the majority of negative associations involve abundant species. In contrast, rare species form mostly positive associations, potentially explaining their persistence in natural communities.

  • 32.
    Calatayud, Joaquín
    et al.
    Umeå University, Faculty of Science and Technology, Department of Physics. Departamento de Ciencias de la Vida, Universidad de Alcala´, Edificio de Ciencias, Ctra. Madrid-Barcelona km. 33,6, Alcala´ de Henares, 28871 Madrid, Spain; Department of Biogeography and Global Change, Museo Nacional de Ciencias Naturales (MNCN-CSIC), C/Jose´ Gutie´rrez Abascal 2, 28006 Madrid, Spain.
    Angel Rodriguez, Miguel
    Molina-Venegas, Rafael
    Leo, Maria
    Luis Horreo, Jose
    Hortal, Joaquin
    Pleistocene climate change and the formation of regional species pools2019In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 286, no 1905, article id 20190291Article in journal (Refereed)
    Abstract [en]

    Although the description of bioregions dates back to the origin of biogeography, the processes originating their associated species pools hive been seldom studied. Ancient historical events are thought to play a fundamental role in configuring bioregions, but the effects of more recent events on these regional biotas are largely unknown. We used a network approach to identify regional and sub-regional faunas of European Carabus beetles and developed a method to explore the relative contribution of dispersal barriers, niche similarities and phylogenetic history on their configuration. We identify a transition zone matching the limit of the ice sheets at the Last Glacial Maximum. While southern species pools are mostly separated by dispersal barriers, in the north species are mainly sorted by their environmental niches. Strikingly, most phylogenetic structuration of Carabus faunas occurred during the Pleistocene. Our results show how extreme recent historical events - such as Pleistocene climate cooling, rather than just deep-time evolutionary processes-can profoundly modify the composition and structure of geographical species pools.

  • 33.
    Capo, Eric
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Molecular Ecology Group, Department of Wildlife, Fish and Environmental Studies, SLU, Umeå, Sweden.
    Spong, Göran
    Molecular Ecology Group, Department of Wildlife, Fish and Environmental Studies, SLU, Umeå, Sweden; Fisheries, Wildlife and Conservation Biology Program, Department of Forestry and Environmental Resources, North Carolina State University, NC, Raleigh, United States.
    Koizumi, Shuntaro
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Puts, Isolde
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Olajos, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Königsson, Helena
    Molecular Ecology Group, Department of Wildlife, Fish and Environmental Studies, SLU, Umeå, Sweden.
    Karlsson, Jan
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Byström, Pär
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Droplet digital PCR applied to environmental DNA, a promising method to estimate fish population abundance from humic-rich aquatic ecosystems2021In: Environmental DNA, E-ISSN 2637-4943, Vol. 3, no 2, p. 343-352Article in journal (Refereed)
    Abstract [en]

    Measures of environmental DNA (eDNA) concentrations in water samples have the potential to be both a cost-efficient and a nondestructive method to estimate fish population abundance. However, the inherent temporal and spatial variability in abiotic and biotic conditions in aquatic systems have been suggested to be a major obstacle to determine relationships between fish eDNA concentrations and fish population abundance. Moreover, once water samples are collected, methodological biases are common, which introduces additional sources of variation to potential relationships between eDNA concentrations and fish population abundance. Here, we evaluate the performance of applying the droplet digital PCR (ddPCR) method to estimate fish population abundance in experimental enclosures. Using large-scale enclosure ecosystems that contain populations of nine-spined stickleback (Pungitius pungitius), we compared the concentrations of fish eDNA (COI mitochondrial region, 134 bp) obtained with the ddPCR method with high precision estimates of fish population abundance (i.e., number of individuals) and biomass. To evaluate the effects of contrasted concentrations of humic substances (potential PCR inhibitors) on the performance of ddPCR assays, we manipulated natural dissolved organic carbon (DOC) concentrations (range 4–11 mg/L) in the enclosures. Additionally, water temperature (+2°C) was manipulated in half of the enclosures. Results showed positive relationships between eDNA concentration and fish abundance and biomass estimates although unexplained variation remained. Still and importantly, fish eDNA estimates from high DOC enclosures were not lowered by potential inhibitory effects with our procedure. Finally, water temperature (although only 2°C difference) was neither detected as a significant factor influencing fish eDNA estimates. Altogether, our work highlights that ddPCR-based eDNA is a promising method for future quantification of fish population abundance in natural systems.

    Download full text (pdf)
    fulltext
  • 34.
    Capo, Eric
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Molecular Ecology Group, Department of Wildlife, Fish and Environmental Studies, SLU, Umeå, Sweden.
    Spong, Göran
    Molecular Ecology Group, Department of Wildlife, Fish and Environmental Studies, SLU, Umeå, Sweden; Fisheries, Wildlife and Conservation Biology Program, Department of Forestry and Environmental Resources, North Carolina State University, NC, Raleigh, United States.
    Königsson, Helena
    Molecular Ecology Group, Department of Wildlife, Fish and Environmental Studies, SLU, Umeå, Sweden.
    Byström, Pär
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Effects of filtration methods and water volume on the quantification of brown trout (Salmo trutta) and Arctic char (Salvelinus alpinus) eDNA concentrations via droplet digital PCR2020In: Environmental DNA, E-ISSN 2637-4943, Vol. 2, no 2, p. 152-160Article in journal (Refereed)
    Abstract [en]

    The quantification of the abundance of aquatic organisms via the use of environmental DNA (eDNA) molecules present in water is potentially a useful tool for efficient and noninvasive population monitoring. However, questions remain about the reliability of molecular methods. Among the factors that can hamper the reliability of the eDNA quantification, we investigated the influence of five filtration methods (filter pore size, filter type) and filtered water volume (1 and 2 L) on the total eDNA and the fish eDNA concentrations of two species, brown trout (Salmo trutta) and Arctic char (Salvelinus alpinus) from tanks with known number of individuals and biomass. We applied a droplet digital PCR (ddPCR) approach to DNA extracted from water samples collected from two cultivation tanks (each of them containing one of the targeted species). Results showed that the quantification of fish eDNA concentrations of both species varies with filtration methods. More specifically, the 0.45-µm Sterivex enclosed filters were identified to recover the highest eDNA concentrations. Difficulties to filter 2 L water samples were present for small pore size filters (≤0.45 µm) and likely caused by filter clogging. To overcome issues related to filter clogging, common in studies aiming to quantify fish eDNA molecules from water samples, we recommend a procedure involving filtration of multiple 1 L water samples with 0.45-µm enclosed filters, to recover both high quality and high concentrations of eDNA from targeted species, and subsequent processing of independent DNA extracts with the ddPCR method.

    Download full text (pdf)
    fulltext
  • 35.
    Carlsson-Graner, Ulla
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Thrall, Peter H.
    Host resistance and pathogen infectivity in host populations with varying connectivity2015In: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 69, no 4, p. 926-938Article in journal (Refereed)
    Abstract [en]

    Theory predicts that hosts and pathogens will evolve higher resistance and aggressiveness in systems where populations are spatially connected than in situations in which populations are isolated and dispersal is more local. In a large cross-inoculation experiment we surveyed patterns of host resistance and pathogen infectivity in anther-smut diseased Viscaria alpina populations from three contrasting areas where populations range from continuous, through patchy but spatially connected to highly isolated demes. In agreement with theory, isolated populations of V. alpina were more susceptible on average than either patchily distributed or continuous populations. While increased dispersal in connected systems increases disease spread, it may also increase host gene flow and the potential for greater host resistance to evolve. In the Viscaria-Microbotryum system, pathogen infectivity mirrored patterns of host resistance with strains from the isolated populations being the least infective and strains from the more resistant continuous populations being the most infective on average, suggesting that high resistance selects for high infectivity. To our knowledge this study is the first to characterize the impacts of varying spatial connectivity on patterns of host resistance and pathogen infectivity in a natural system.

  • 36.
    Chavhan, Yashraj
    et al.
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Dey, Sutirth
    Indian Institute of Science Education and Research (IISER) Pune, Pune, India.
    Lind, Peter A
    Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR). Umeå University, Faculty of Science and Technology, Department of Molecular Biology (Faculty of Science and Technology).
    Bacteria evolve macroscopic multicellularity by the genetic assimilation of phenotypically plastic cell clustering2023In: Nature Communications, E-ISSN 2041-1723, Vol. 14, no 1, article id 3555Article in journal (Refereed)
    Abstract [en]

    The evolutionary transition from unicellularity to multicellularity was a key innovation in the history of life. Experimental evolution is an important tool to study the formation of undifferentiated cellular clusters, the likely first step of this transition. Although multicellularity first evolved in bacteria, previous experimental evolution research has primarily used eukaryotes. Moreover, it focuses on mutationally driven (and not environmentally induced) phenotypes. Here we show that both Gram-negative and Gram-positive bacteria exhibit phenotypically plastic (i.e., environmentally induced) cell clustering. Under high salinity, they form elongated clusters of ~ 2 cm. However, under habitual salinity, the clusters disintegrate and grow planktonically. We used experimental evolution with Escherichia coli to show that such clustering can be assimilated genetically: the evolved bacteria inherently grow as macroscopic multicellular clusters, even without environmental induction. Highly parallel mutations in genes linked to cell wall assembly formed the genomic basis of assimilated multicellularity. While the wildtype also showed cell shape plasticity across high versus low salinity, it was either assimilated or reversed after evolution. Interestingly, a single mutation could genetically assimilate multicellularity by modulating plasticity at multiple levels of organization. Taken together, we show that phenotypic plasticity can prime bacteria for evolving undifferentiated macroscopic multicellularity.

    Download full text (pdf)
    fulltext
  • 37. Chen, Xiaojie
    et al.
    Brännström, Åke
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics. Evolution and Ecology Program, International Institute for Applied Systems Analysis (IIASA), Laxenburg, Austria.
    Dieckmann, Ulf
    Parent-preferred dispersal promotes cooperation in structured populations2019In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 286, no 1895, article id 20181949Article in journal (Refereed)
    Abstract [en]

    Dispersal is a key process for the emergence of social and biological behaviours. Yet, little attention has been paid to dispersal's effects on the evolution of cooperative behaviour in structured populations. To address this issue, we propose two new dispersal modes, parent-preferred and offspring-preferred dispersal, incorporate them into the birth-death update rule, and consider the resultant strategy evolution in the prisoner's dilemma on random-regular, small-world, and scale-free networks, respectively. We find that parent-preferred dispersal favours the evolution of cooperation in these different types of population structures, while offspring-preferred dispersal inhibits the evolution of cooperation in homogeneous populations. On scale-free networks when the strength of parent-preferred dispersal is weak, cooperation can be enhanced at intermediate strengths of offspring-preferred dispersal, and cooperators can coexist with defectors at high strengths of offspring-preferred dispersal. Moreover, our theoretical analysis based on the pair-approximation method corroborates the evolutionary outcomes on random-regular networks. We also incorporate the two new dispersal modes into three other update rules (death-birth, imitation, and pairwise comparison updating), and find that similar results about the effects of parent-preferred and offspring-preferred dispersal can again be observed in the aforementioned different types of population structures. Our work, thus, unveils robust effects of preferential dispersal modes on the evolution of cooperation in different interactive environments.

  • 38.
    Cherif, Mehdi
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Stoichiometry and Population Growth in Osmotrophs and Non‐Osmotrophs2016In: eLS, John Wiley & Sons, 2016, p. 1-6Chapter in book (Refereed)
    Abstract [en]

    Growth is a process fundamental to life. It implies an increase in not only energy and information but also matter content. Recent advances in ecology have demonstrated that the elemental composition of organisms – their stoichiometry – is inextricably linked to their growth rate. Unbalances between the demands of elements for growth and their relative availabilities often result in elemental limitation. Also, different cellular components have different elemental compositions, and thus changes in allocation between uptake and assembly machineries affect both growth rate and elemental composition at the organismal level. Osmotrophs (including autotrophs) acquire essential elements through a vast set of separate molecules, resulting in more flexible stoichiometries compared to non-osmotrophs that ingest their preys in one package. Relationships between elemental composition and growth rate should be considered differently for individuals and for populations, as processes and mechanisms differ between the two scales, and more generally among the various biological scales.

  • 39. Cornforth, Daniel M
    et al.
    Sumpter, David J T
    Brown, Sam P
    Brännström, Åke
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    Synergy and group size in microbial cooperation2012In: American Naturalist, ISSN 0003-0147, E-ISSN 1537-5323, Vol. 180, no 3, p. 296-305Article in journal (Refereed)
    Abstract [en]

    Abstract Microbes produce many molecules that are important for their growth and development, and the exploitation of these secretions by nonproducers has recently become an important paradigm in microbial social evolution. Although the production of these public-goods molecules has been studied intensely, little is known of how the benefits accrued and the costs incurred depend on the quantity of public-goods molecules produced. We focus here on the relationship between the shape of the benefit curve and cellular density, using a model assuming three types of benefit functions: diminishing, accelerating, and sigmoidal (accelerating and then diminishing). We classify the latter two as being synergistic and argue that sigmoidal curves are common in microbial systems. Synergistic benefit curves interact with group sizes to give very different expected evolutionary dynamics. In particular, we show that whether and to what extent microbes evolve to produce public goods depends strongly on group size. We show that synergy can create an "evolutionary trap" that can stymie the establishment and maintenance of cooperation. By allowing density-dependent regulation of production (quorum sensing), we show how this trap may be avoided. We discuss the implications of our results on experimental design.

  • 40. Crispo, Erika
    et al.
    DiBattista, Joseph D.
    Correa, Cristian
    Thibert-Plante, Xavier
    Department of Biology and Redpath Museum, McGill University, Montreal, Quebec, Canada.
    McKellar, Ann E.
    Schwartz, Amy K.
    Berner, Daniel
    De Leon, Luis F.
    Hendry, Andrew P.
    The evolution of phenotypic plasticity in response to anthropogenic disturbance2010In: Evolutionary Ecology Research, ISSN 1522-0613, E-ISSN 1937-3791, Vol. 12, no 1, p. 47-66Article in journal (Refereed)
    Abstract [en]

    Questions: Do evolutionary changes in phenotypic plasticity occur after anthropogenic disturbance? Do these changes tend to be increases or decreases in plasticity? How do these evolutionary patterns differ among taxa and trait types? Does evolution of plasticity change with time since the disturbance?

    Data incorporated: Evolutionary rates for plasticity estimated from 20 studies that have compared a plastic response in two or more populations, at least one of which had experienced an anthropogenic disturbance in nature and at least one of which had not.

    Method of analysis: We estimate evolutionary rates (darwins and haldanes) for plasticity for each study, which represent the amount of evolutionary change in plasticity. We then perform analyses of covariance, with the evolutionary rate numerator (amount of evolutionary change) as a response variable, taxa and trait type as predictor variables, and the amount of evolutionary time as a covariate.

    Conclusions:We find that plasticity has evolved in several cases, including both increases and decreases in the levels of plasticity following anthropogenic disturbances. The typical direction of this evolutionary response depends on an interaction between taxon and trait type. For instance, invertebrates sometimes show the evolution of increased  plasticity for life-history traits, but the evolution of decreased plasticity for morphological traits. Plants, on the other hand, show no trends in the direction of plasticity evolution.

  • 41.
    Cīrulis, Aivars
    et al.
    Department of Biology, Lund University, Lund, Sweden; Laboratory of Microbiology and Pathology, Institute of Food Safety, Animal Health and Environment Bior, Riga, Latvia; Faculty of Biology, University of Latvia, Riga, Latvia.
    Nordén, Anna K
    Department of Biology, Lund University, Lund, Sweden.
    Churcher, Allison M
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Ramm, Steven A
    Department of Evolutionary Biology, Bielefeld University, Bielefeld, Germany; Umr 6553 Ecobio, Université de Rennes, Rennes, France.
    Zadesenets, Kira S
    Department of Molecular Genetics, Cell Biology and Bionformatics, The Federal Research Center Institute of Cytology and Genetics Sb Ras, Novosibirsk, Russian Federation.
    Abbott, Jessica K
    Department of Biology, Lund University, Lund, Sweden.
    Sex-limited experimental evolution drives transcriptomic divergence in a hermaphrodite2024In: Genome Biology and Evolution, ISSN 1759-6653, E-ISSN 1759-6653, Vol. 16, no 1, article id evad235Article in journal (Refereed)
    Abstract [en]

    The evolution of gonochorism from hermaphroditism is linked with the formation of sex chromosomes, as well as the evolution of sex-biased and sex-specific gene expression to allow both sexes to reach their fitness optimum. There is evidence that sexual selection drives the evolution of male-biased gene expression in particular. However, previous research in this area in animals comes from either theoretical models or comparative studies of already old sex chromosomes. We therefore investigated changes in gene expression under 3 different selection regimes for the simultaneous hermaphrodite Macrostomum lignano subjected to sex-limited experimental evolution (i.e. selection for fitness via eggs, sperm, or a control regime allowing both). After 21 and 22 generations of selection for male-specific or female-specific fitness, we characterized changes in whole-organism gene expression. We found that female-selected lines had changed the most in their gene expression. Although annotation for this species is limited, gene ontology term and Kyoto Encyclopedia of Genes and Genomes pathway analyses suggest that metabolic changes (e.g. biosynthesis of amino acids and carbon metabolism) are an important adaptive component. As predicted, we found that the expression of genes previously identified as testis-biased candidates tended to be downregulated in the female-selected lines. We did not find any significant expression differences for previously identified candidates of other sex-specific organs, but this may simply reflect that few transcripts have been characterized in this way. In conclusion, our experiment suggests that changes in testis-biased gene expression are important in the early evolution of sex chromosomes and gonochorism.

    Download full text (pdf)
    fulltext
  • 42.
    Dawson, Michael N.
    et al.
    School of Natural Sciences, University of California, 5200 North Lake Road, CA, Merced, United States.
    Axmacher, Jan C.
    UCL Department of Geography, University College London, London, United Kingdom.
    Beierkuhnlein, Carl
    Biogeography, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Universitätstr. 30, Bayreuth, Germany.
    Blois, Jessica
    School of Natural Sciences, University of California, 5200 North Lake Road, CA, Merced, United States.
    Bradley, Bethany A.
    Department of Environmental Conservation, University of Massachusetts, MA, Amherst, United States.
    Cord, Anna F.
    Department of Computational Landscape Ecology, Helmholtz Centre for Environmental Research - UFZ, Permoserstr. 15, Leipzig, Germany.
    Dengler, Jürgen
    Plant Ecology, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Universitätstr. 30, Bayreuth, Germany; German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena- Leipzig, Deutscher Platz 5e, Leipzig, Germany.
    He, Kate S.
    Department of Biological Sciences, Murray State University, KY, Murray, United States.
    Heaney, Lawrence R.
    Field Museum of Natural History, 1400 S Lake Shore Drive, IL, Chicago, United States.
    Jansson, Roland
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Mahecha, Miguel D.
    Max Planck Institute for Biogeochemistry, Jena, Germany; German Centre for Integrative Biodiversity Research (iDiv), Halle-Jena-Leipzig, Leipzig, Germany.
    Myers, Corinne
    Department of Earth and Planetary Sciences, University of New Mexico, 1 Northrop Hall, NM, Albuquerque, United States.
    Nogués-Bravo, David
    Center for Macroecology, Evolution and Climate, Natural History Museum of Denmark, University of Copenhagen, Universitetsparken 15, Copenhagen Ø, Denmark.
    Papadopoulou, Anna
    Integrative Ecology Group, Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas (EBD-CSIC), Avenida Américo Vespucio s/n, Sevilla, Spain.
    Reu, Björn
    Institute of Biology, University of Leipzig, Leipzig, Germany.
    Rodríguez-Sánchez, Francisco
    Integrative Ecology Group, Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas (EBD-CSIC), Avenida Américo Vespucio s/n, Sevilla, Spain.
    Steinbauer, Manuel J.
    Section Ecoinformatics and Biodiversity, Department of Bioscience, Aarhus University, Aarhus, Denmark.
    Stigall, Alycia
    Ohio University, Department of Geological Sciences, OHIO Center for Ecology and Evolutionary Studies, 316 Clippinger Laboratories, OH, Athens, United States.
    Tuanmu, Mao-Ning
    Department of Ecology and Evolutionary Biology, Yale University, 165 Prospect Street, CT, New Haven, United States; Biodiversity Research Center, Academia Sinica, Taipei, Taiwan.
    Gavin, Daniel G.
    Department of Geography, University of Oregon, OR, Eugene, United States.
    A second horizon scan of biogeography: Golden ages, Midas touches, and the Red Queen2016In: Frontiers of Biogeography, E-ISSN 1948-6596, Vol. 8, no 4, article id e29770Article in journal (Refereed)
    Abstract [en]

    Are we entering a new 'Golden Age' of biogeography, with continued development of infrastructure and ideas? We highlight recent developments, and the challenges and opportunities they bring, in light of the snapshot provided by the 7th biennial meeting of the International Biogeography Society (IBS 2015). We summarize themes in and across 15 symposia using narrative analysis and word clouds, which we complement with recent publication trends and 'research fronts'. We find that biogeography is still strongly defined by core sub-disciplines that reflect its origins in botanical, zoological (particularly bird and mammal), and geographic (e.g., island, montane) studies of the 1800s. That core is being enriched by large datasets (e.g. of environmental variables, 'omics', species' occurrences, traits) and new techniques (e.g., advances in genetics, remote sensing, modeling) that promote studies with increasing detail and at increasing scales; disciplinary breadth is being diversified (e.g., by developments in paleobiogeography and microbiology) and integrated through the transfer of approaches and sharing of theory (e.g., spatial modeling and phylogenetics in evolutionary-ecological contexts). Yet some subdisciplines remain on the fringe (e.g., marine biogeography, deep-time paleobiogeography), new horizons and new theory may be overshadowed by popular techniques (e.g., species distribution modelling), and hypotheses, data, and analyses may each be wanting. Trends in publication suggest a shift away from traditional biogeography journals to multidisciplinary or open access journals. Thus, there are currently many opportunities and challenges as biogeography increasingly addresses human impacts on, and stewardship of, the planet (e.g., Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services). As in the past, biogeographers doubtless will continue to be engaged by new data and methods in exploring the nexus between biology and geography for decades into the future. But golden ages come and go, and they need not touch every domain in a discipline nor affect subdisciplines at the same time; moreover, what appears to be a Golden Age may sometimes have an undesirable 'Midas touch'. Contexts within and outwith biogeography-e.g., methods, knowledge, climate, biodiversity, politics-are continually changing, and at times it can be challenging to establish or maintain relevance. In so many races with the Red Queen, we suggest that biogeography will enjoy greatest success if we also increasingly engage with the epistemology of our discipline.

    Download full text (pdf)
    fulltext
  • 43. De Block, Marjan
    et al.
    Slos, Stefanie
    Johansson, Frank
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Stoks, Robby
    Integrating life history and physiology to understand latitudinal size variation in a damselfly2008In: Ecography, ISSN 0906-7590, E-ISSN 1600-0587, Vol. 31, p. 115-123Article in journal (Refereed)
    Abstract [en]

    Our understanding of latitudinal life history patterns may benefit by jointly considering age and mass at maturity and growth rate. Additional insight may be gained by exploring potential constraints through pushing growth rates to their maximum and scoring physiological cost-related variables. Therefore, we reared animals of a univoltine Spanish and Belgian population and of a semivoltine Swedish population of the damselfly Enallagma cyathigerum (spanning a latitude gradient of ca 2350 km) in a common environment from the eggs until adult emergence and exposed them to a transient starvation period to induce compensatory growth. Besides age and mass at maturity and growth rate we also scored investment in energy storage (i.e. triglycerides) and immune function (i.e. total activity of phenoloxidase). At emergence, body mass was greater in Spain and Sweden and lower in Belgium, suggesting a genetic component for the U-shaped latitudinal pattern that was found also in a previous study based on field-collected adults. The mass difference between univoltine populations can be explained by the shorter development time in the Belgian population, and this despite a higher growth rate, a pattern consistent with undercompensating countergradient variation. In line with the assumed shorter growth seasons, Belgian and Swedish animals showed higher routine growth rates and compensatory growth after transient starvation. Despite a strong link with metabolic rates (as measured by oxygen consumption) populations with higher routine growth rates had no lower fat content and had higher immune function (i.e. immune function decreased from Sweden to Spain), which was unexpected. Rapid compensatory growth did, however, result in a lowered immune function. This may contribute to the absence of perfect compensating countergradient variation in the Belgian population and the lowest routine growth rates in the Spanish population. Our results underscore the importance of integrating key life historical with physiological traits for understanding latitudinal population differentiation.

  • 44.
    de La Torre, Amanda R.
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Department of Plant Sciences, University of California–Davis, Davis, CA.
    Li, Zhen
    Van de Peer, Yves
    Ingvarsson, Pär K.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Department of Plant Biology, Uppsala Biocenter, Swedish University of Agr icultural Sciences, Uppsala, Sweden.
    Contrasting Rates of Molecular Evolution and Patterns of Selection among Gymnosperms and Flowering Plants2017In: Molecular biology and evolution, ISSN 0737-4038, E-ISSN 1537-1719, Vol. 34, no 6, p. 1363-1377Article in journal (Refereed)
    Abstract [en]

    The majority of variation in rates of molecular evolution among seed plants remains both unexplored and unexplained. Although some attention has been given to flowering plants, reports of molecular evolutionary rates for their sister plant clade (gymnosperms) are scarce, and to our knowledge differences in molecular evolution among seed plant clades have never been tested in a phylogenetic framework. Angiosperms and gymnosperms differ in a number of features, of which contrasting reproductive biology, life spans, and population sizes are the most prominent. The highly conserved morphology of gymnosperms evidenced by similarity of extant species to fossil records and the high levels of macrosynteny at the genomic level have led scientists to believe that gymnosperms are slow-evolving plants, although some studies have offered contradictory results. Here, we used 31,968 nucleotide sites obtained from orthologous genes across a wide taxonomic sampling that includes representatives of most conifers, cycads, ginkgo, and many angiosperms with a sequenced genome. Our results suggest that angiosperms and gymnosperms differ considerably in their rates of molecular evolution per unit time, with gymnosperm rates being, on average, seven times lower than angiosperm species. Longer generation times and larger genome sizes are some of the factors explaining the slow rates of molecular evolution found in gymnosperms. In contrast to their slow rates of molecular evolution, gymnosperms possess higher substitution rate ratios than angiosperm taxa. Finally, our study suggests stronger and more efficient purifying and diversifying selection in gymnosperm than in angiosperm species, probably in relation to larger effective population sizes.

    Download full text (pdf)
    fulltext
  • 45.
    De La Torre, Amanda R
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Lin, Yao-Cheng
    Van de Peer, Yves
    Ingvarsson, Pär K
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Genome-wide analysis reveals diverged patterns of codon bias, gene expression, and rates of sequence evolution in Picea gene families2015In: Genome Biology and Evolution, ISSN 1759-6653, E-ISSN 1759-6653, Vol. 7, no 4, p. 1002-1015Article in journal (Refereed)
    Abstract [en]

    The recent sequencing of several gymnosperm genomes has greatly facilitated studying the evolution of their genes and gene families. In this study, we examine the evidence for expression-mediated selection in the first two fully sequenced representatives of the gymnosperm plant clade (Picea abies and Picea glauca). We use genome-wide estimates of gene expression (> 50,000 expressed genes) to study the relationship between gene expression, codon bias, rates of sequence divergence, protein length, and gene duplication. We found that gene expression is correlated with rates of sequence divergence and codon bias, suggesting that natural selection is acting on Picea protein-coding genes for translational efficiency. Gene expression, rates of sequence divergence, and codon bias are correlated with the size of gene families, with large multicopy gene families having, on average, a lower expression level and breadth, lower codon bias, and higher rates of sequence divergence than single-copy gene families. Tissue-specific patterns of gene expression were more common in large gene families with large gene expression divergence than in single-copy families. Recent family expansions combined with large gene expression variation in paralogs and increased rates of sequence evolution suggest that some Picea gene families are rapidly evolving to cope with biotic and abiotic stress. Our study highlights the importance of gene expression and natural selection in shaping the evolution of protein-coding genes in Picea species, and sets the ground for further studies investigating the evolution of individual gene families in gymnosperms.

    Download full text (pdf)
    fulltext
  • 46.
    Desvars, Amélie
    et al.
    Cirad, UMR15 Contrôle des Maladies Animales Exotiques et Emergentes, Montpellier, France; INRA, UMR1309 Contrôle des Maladies Animales Exotiques et Emergentes, Montpellier, France.
    Grimaud, Y.
    Groupement de Défense Sanitaire, La Plaine des Cafres, La Réunion, France.
    Guis, H.
    Cirad, UMR15 Contrôle des Maladies Animales Exotiques et Emergentes, Montpellier, France; INRA, UMR1309 Contrôle des Maladies Animales Exotiques et Emergentes, Montpellier, France.
    Esnault, O.
    Groupement de Défense Sanitaire, La Plaine des Cafres, La Réunion, France.
    Allène, X.
    Cirad, UMR15 Contrôle des Maladies Animales Exotiques et Emergentes, Montpellier, France; INRA, UMR1309 Contrôle des Maladies Animales Exotiques et Emergentes, Montpellier, France.
    Gardès, L.
    Cirad, UMR15 Contrôle des Maladies Animales Exotiques et Emergentes, Montpellier, France; INRA, UMR1309 Contrôle des Maladies Animales Exotiques et Emergentes, Montpellier, France.
    Balenghien, T.
    Cirad, UMR15 Contrôle des Maladies Animales Exotiques et Emergentes, Montpellier, France; INRA, UMR1309 Contrôle des Maladies Animales Exotiques et Emergentes, Montpellier, France.
    Baldet, T.
    Cirad, UMR15 Contrôle des Maladies Animales Exotiques et Emergentes, Montpellier, France; INRA, UMR1309 Contrôle des Maladies Animales Exotiques et Emergentes, Montpellier, France.
    Delécolle, J.C.
    Institut de Parasitologie et de Pathologie Tropicale de Strasbourg (IPPTS), Strasbourg, France.
    Garros, C.
    Cirad, UMR15 Contrôle des Maladies Animales Exotiques et Emergentes, Montpellier, France; INRA, UMR1309 Contrôle des Maladies Animales Exotiques et Emergentes, Montpellier, France.
    First overview of the Culicoides Latreille (Diptera: Ceratopogonidae) livestock associated species of Reunion Island, Indian Ocean2015In: Acta Tropica, ISSN 0001-706X, E-ISSN 1873-6254, Vol. 142, p. 5-19Article in journal (Refereed)
    Abstract [en]

    This study establishes the first faunistic inventory of livestock associated Culicoides (Diptera: Ceratopogonidae) species of Reunion Island (Indian Ocean), where bluetongue and epizootic hemorrhagic disease are regularly recorded. Single night-catches were performed at 41 sites using light suction traps at altitudes ranging from 0 to 1525. m, from March to April 2005. Five species were recorded: Culicoides imicola, Culicoides bolitinos, Culicoides enderleini, Culicoides grahamii, and Culicoides kibatiensis, among which at least the first three species are known to be involved in virus transmission to ruminants and equids. This is the first record of C. bolitinos, C. kibatiensis, and C. enderleini on the island. C. imicola was the most abundant species along the sea coast. C. bolitinos was more abundant inland and on two sites on the east coast. C. kibatiensis and C. grahamii were less abundant than the other three species and limited to two foci.

    Spatial distribution analysis of the different species showed that C. bolitinos, C. enderleini and C. imicola were collected at low altitudes, while the other two species were found at higher altitude. A morphological identification key for adult females and males is given, as well as cytochrome oxydase subunit I sequences. Phylogenetic reconstructions showed a clear divergence between C. bolitinos from Reunion Island and mainland Africa. This monograph will help to identify the Culicoides species in the poorly known entomological fauna of the south-western Indian Ocean region.

  • 47.
    Dibattista, Joseph D.
    et al.
    Redpath Museum and Department of Biology, McGill University, Montréal, Québec, Canada .
    Feldheim, Kevin A.
    Field Museum, Pritzker Laboratory for Molecular Systematics and Evolution, Chicago, IL, USA.
    Thibert-Plante, Xavier
    Redpath Museum and Department of Biology, McGill University, Montréal, Québec, Canada.
    Gruber, Samuel H.
    Division of Marine Biology and Fisheries, Rosenstiel School of Marine and Atmospheric Science, Miami, FL, USA.
    Hendry, Andrew P.
    Redpath Museum and Department of Biology, McGill University, Montréal, Québec, Canada.
    A genetic assessment of polyandry and breeding-site fidelity in lemon sharks2008In: Molecular Ecology, ISSN 0962-1083, E-ISSN 1365-294X, Vol. 17, no 14, p. 3337-3351Article in journal (Refereed)
    Abstract [en]

    We here employ 11 microsatellite markers and recently developed litter reconstruction methods to infer mating system parameters (i.e. polyandry and breeding-site fidelity) at a lemon shark nursery site in Marquesas Key, Florida. Four hundred and eight juvenile or subadult sharks were genotyped over eight complete breeding seasons. Using this information, we were able to infer family structure, as well as fully or partially reconstruct genotypes of 46 mothers and 163 fathers. Multiple litter reconstruction methods were used, and novel simulations helped define apparent bias and precision of at least some mating system parameters. For Marquesas Key, we find that adult female lemon sharks display high levels of polyandry (81% of all litters sampled) and stronger fidelity to the nursery site than do males. Indeed, few male sharks sired offspring from more than one litter during the course of the study. These findings were quite similar to previous results from another lemon shark nursery site (Bimini, Bahamas), suggesting conserved mating system parameters despite significant variation in early life-history traits (i.e. body size and growth) among sites. The finding of at least some site fidelity in females also supports the need for careful conservation of each nursery.

  • 48. Dixon, Christopher J
    et al.
    Schoenswetter, Peter
    Suda, Jan
    Wiedermann, Magdalena M
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Schneeweiss, Gerald M
    Reciprocal Pleistocene origin and postglacial range formation of an allopolyploid and its sympatric ancestors (Androsace adfinis group, Primulaceae)2009In: Molecular Phylogenetics and Evolution, ISSN 1055-7903, E-ISSN 1095-9513, Vol. 50, no 1, p. 74-83Article in journal (Refereed)
    Abstract [en]

    The biogeographic history of polyploids and their lower-ploid ancestors is an important feature to achieve a better understanding of polyploid evolution. This is exemplified here using the ecologically congruent members of the Androsace adfinis group (Primulaceae) endemic to the southwestern European Alps. Employing relative genome size, AFLP fingerprint and chloroplast sequence haplotype data, we show that Androsace brigantiaca is a recent (probably no more than 0.2 million years) allopolyploid derivative of the geographically close A adfinis and A puberula, which formed reciprocally in a comparatively restricted area in the southern Southwestern Alps. Bayesian admixture analysis-also of artificial additive AFLP profiles-shows that the nuclear genome of A. brigantiaca is significantly biased towards the puberula-genome irrespective of maternal parentage. Nevertheless, there is no evidence for genetic interaction (hybridization, introgression) of A brigantiaca with either of its ancestors, including the widely sympatric A. puberula. Sympatry might be facilitated by ecological displacement on a local scale or might be a transitory phase on the way to competitive replacement via, for instance, polyploid superiority.

  • 49. Drotz, Marcus K
    et al.
    Brodin, Tomas
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Nilsson, Anders N
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Changing Names with Changed Address: Integrated Taxonomy and Species Delimitation in the Holarctic Colymbetes paykulli Group (Coleoptera: Dytiscidae)2015In: PLOS ONE, E-ISSN 1932-6203, Vol. 10, no 11, article id e0143577Article in journal (Refereed)
    Abstract [en]

    Species delimitation of geographically isolated forms is a long-standing problem in less studied insect groups. Often taxonomic decisions are based directly on morphologic variation, and lack a discussion regarding sample size and the efficiency of migration barriers or dispersal/migration capacity of the studied species. These problems are here exemplified in a water beetle complex from the Bering Sea region that separates North America from Eurasia. Only a few sampled specimens occur from this particular area and they are mostly found in museum and private collections. Here we utilize the theory of integrated taxonomy to discuss the speciation of the Holarctic Colymbetes paykulli water beetle complex, which historically has included up to five species of which today only two are recognized. Three delimitation methods are used; landmark based morphometry of body shape, variation in reticulation patterns of the pronotum exo-skeleton and sequence variation of the partial mitochondrial gene Cyt b. Our conclusion is that the Palearctic and Nearctic populations of C. paykulli are given the status of separate species, based on the fact that all methods showed significant separation between populations. As a consequence the name of the Palearctic species is C. paykulli Erichson and the Nearctic species should be known as C. longulus LeConte. There is no clear support for delineation between Palearctic and Nearctic populations of C. dahuricus based on mtDNA. However, significant difference in size and reticulation patterns from the two regions is shown. The combined conclusion is that the C. dahuricus complex needs a more thorough investigation to fully disentangle its taxonomic status. Therefore it is here still regarded as a Holarctic species. This study highlights the importance to study several diagnosable characters that has the potential to discriminate evolutionary lineage during speciation.

    Download full text (pdf)
    fulltext
  • 50. Drotz, Marcus K.
    et al.
    Brodin, Tomas
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Nilsson, Anders N.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Multiple origins of elytral reticulation modifications in the west palearctic Agabus bipustulatus complex (Coleoptera, Dytiscidae)2010In: PLoS ONE, ISSN 1932-6203, Vol. 5, no 2, article id e9034Article in journal (Refereed)
    Abstract [en]

    The Agabus bipustulatus complex includes one of Europe's most widely distributed and common diving beetles. This complex, which is known for its large morphological variation, has a complex demographic and altitudinal variation in elytral reticulation. The various depth of the reticulation imprint, both in smaller and larger meshes, results in both mat and shiny individuals, as well as intermediate forms. The West Palearctic lowland is inhabited by a sexually dimorphic form, with shiny males and mat females. In mountain regions, shiny individuals of both sexes are found intermixed with mat individuals or in pure populations in central and southern areas, whereas pure populations of mat individuals are exclusively found in the northern region at high altitude. Sexual selection is proposed as a driving force in shaping this variation. However, the occurrence of different types of reticulation in both sexes and disjunct geographical distribution patterns suggest an additional function of the reticulation. Here we investigate the phylogeographical history, genetic structure and reticulation variation of several named forms within the Agabus bipustulatus complex including A. nevadensis. The molecular analyses recognised several well-supported clades within the complex. Several of the named forms had two or more independent origins. Few south European populations were uniform in reticulation patterns, and the males were found to display large variation. Reticulation diversity and population genetic variability were clearly correlated to altitude, but no genetic differences were detected among populations with mixed or homogenous forms. Observed reduction in secondary reticulation in female and increased variance in male at high altitude in South Europe may be explained by the occurrence of an additional selective force, beside sexual selection. The combined effect of these selective processes is here demonstrated in an extreme case to generate isolation barriers between populations at high altitudes. Here we discuss this selective force in relation to thermal selection.

    Download full text (pdf)
    fulltext
12345 1 - 50 of 243
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf