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  • 1551.
    Wang, B.
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Climent, J.
    Wang, Xiao-Ru
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Horizontal gene transfer from a flowering plant to the insular pine Pinus canariensis (Chr. Sm. Ex DC in Buch)2015Inngår i: Heredity, ISSN 0018-067X, E-ISSN 1365-2540, Vol. 114, nr 4, s. 413-418Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Horizontal gene transfer (HGT) is viewed as very common in the plant mitochondrial (mt) genome, but, to date, only one case of HGT has been found in gymnosperms. Here we report a new case of HGT, in which a mt nad5-1 fragment was transferred from an angiosperm to Pinus canariensis. Quantitative assay and sequence analyses showed that the foreign nad5-1 is located in the mt genome of P. canariensis and is nonfunctional. An extensive survey in the genus Pinus revealed that the angiosperm-derived nad5-1 is restricted to P. canariensis and present across the species' range. Molecular dating based on chloroplast DNA suggested that the HGT event occurred in the late Miocene after P. canariensis split from its closest relatives, and that the foreign copy became fixed in P. canariensis owing to drift during its colonization of the Canary Islands. The mechanism of this HGT is unclear but it was probably achieved through either direct cell-cell contact or external vectors. Our discovery provides evidence for an important role of HGT in plant mt genome evolution.

  • 1552.
    Wang, Baosheng
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Hybridization and Evolution in the Genus Pinus2013Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Gene flow and hybridization are pervasive in nature, and can lead to different evolutionary outcomes. They can either accelerate divergence and promote speciation or reverse differentiation. The process of divergence and speciation are strongly influenced by both neutral and selective forces. Disentangling the interplay between these processes in natural systems is important for understanding the general importance of interspecific gene flow in generating novel biodiversity in plants. This thesis first examines the importance of introgressive hybridization in the evolution of the genus Pinus as a whole, and then focusing on specific pine species, investigates the role of geographical, environmental and demographical factors in driving divergence and adaptation.

    By examining the distribution of cytoplasmic DNA variation across the wide biogeographic range of the genus Pinus, I revealed historical introgression and mtDNA capture events in several groups of different pine species. This finding suggests that introgressive hybridization was common during past species’ range contractions and expansions and thus has played an important role in the evolution of the genus. To understand the cause and process of hybrid speciation, I focused on the significant case of hybrid speciation in Pinus densata. I established the hybridization, colonization and differentiation processes that defined the origin of this species. I found P. densata originated via multiple hybridization events in the late Miocene. The direction and intensity of introgression with two parental species varied among geographic regions of this species. During the colonization on Tibetan Plateau from the ancestral hybrid zone, consecutive bottlenecks and surfing of rare alleles caused a significant reduction in genetic diversity and strong population differentiation. Divergence within P. densata started from the late Pliocene onwards, induced by regional topographic changes and Pleistocene glaciations. To address the role of neutral and selective forces on genetic divergence, I examined the association of ecological and geographical distance with genetic distance in Pinus yunnanensis populations. I found both neutral and selective forces have contributed to population structure and differentiation in P. yunnanensis, but their relative contributions varied across the complex landscape. Finally, I evaluated genetic diversity in the Vietnamese endemic Pinus krempfii. I found extremely low genetic diversity in this species, which is explained by a small ancestral population, short-term population expansion and recent population decline and habitat fragmentation.

    These findings highlight the role of hybridization in generating novel genetic diversity and the different mechanisms driving divergence and adaptation in the genus Pinus

  • 1553.
    Wang, Jing
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå Plant Science Centre (UPSC).
    Abbott, Richard
    School of Biology, Mitchell Building, University of St Andrews, St Andrews.
    Ingvarsson, Pär
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå Plant Science Centre (UPSC).
    Liu, Jianquan
    Key Laboratory of Bio-Source and Environmental Conservation, School of Life Science, Sichuan University.
    Increased genetic divergence between two closely related fir species in areas of range overlap2014Inngår i: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 4, nr 7, s. 1019-1029Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Because of introgressive hybridization, closely related species can be more similar to each other in areas of range overlap (parapatry or sympatry) than in areas where they are geographically isolated from each other (allopatry). Here, we report the reverse situation based on nuclear genetic divergence between two fir species, Abies chensiensis and Abies fargesii, in China, at sites where they are parapatric relative to where they are allopatric. We examined genetic divergence across 126 amplified fragment length polymorphism (AFLP) markers in a set of 172 individuals sampled from both allopatric and parapatric populations of the two species. Our analyses demonstrated that AFLP divergence was much greater between the species when comparisons were made between parapatric populations than between allopatric populations. We suggest that selection in parapatry may have largely contributed to this increased divergence.

  • 1554.
    Wang, Jing
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. Centre for Integrative Genetics, Department of Animal and Aquacultural Sciences, Faculty of Life Sciences, Norwegian University of Life Science.
    Ding, Jihua
    Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences.
    Tan, Biyue
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. Stora Enso AB.
    Robinson, Kathryn M.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysiologisk botanik.
    Michelson, Ingrid H.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysiologisk botanik.
    Johansson, Anna
    Wallenberg Advanced Bioinformatics Infrastructure, Science for Life Laboratory, Uppsala University.
    Nystedt, Björn
    Wallenberg Advanced Bioinformatics Infrastructure, Science for Life Laboratory, Uppsala University.
    Scofield, Douglas G.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. Department of Ecology and Genetics, Evolutionary Biology, Uppsala University.
    Nilsson, Ove
    Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences.
    Jansson, Stefan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysiologisk botanik.
    Street, Nathaniel R.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysiologisk botanik.
    Ingvarsson, Pär K.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences.
    A major locus controls local adaptation and adaptive life history variation in a perennial plantManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Background: The initiation of growth cessation and dormancy represent critical life-history trade-offs between survival and growth, and have important fitness effects in perennial plants. Such adaptive life history traits often show strong local adaptation along environmental gradients but despite their importance, the genetic architecture of these traits remains poorly understood.

    Results: We integrate whole genome re-sequencing with environmental and phenotypic data from common garden experiments to investigate the genomic basis of local adaptation across a latitudinal gradient in European aspen (Populus tremula). We discover a single genomic region containing the PtFT2 gene that mediates local adaptation in the timing of bud set and that explains 65% of the observed genetic variation in bud set. This locus is the likely target of a recent selective sweep that originated right before or during colonization of northern Scandinavia following the last glaciation. Field and greenhouse experiments confirm that variation in PtFT2 gene expression affect the phenotypic variation in bud set that we observe in wild natural populations.

    Conclusions: Our results reveal a major effect locus that determine the timing of bud set and that have facilitated rapid adaptation to shorter growing seasons and colder climates in European aspen. The discovery of a single locus explaining a substantial fraction of the variation in a key life history trait is remarkable given that such traits are generally considered to be highly polygenic. These findings provide a dramatic illustration of how loci of large-effect for adaptive traits can arise and be maintained over large geographical scales in natural populations.

  • 1555.
    Wang, Jing
    et al.
    Umea Univ, Umea Plant Sci Ctr, Dept Ecol & Environm Sci, SE-90187 Umea, Sweden..
    Street, Nathaniel R.
    Umea Univ, Umea Plant Sci Ctr, Dept Plant Physiol, SE-90187 Umea, Sweden..
    Scofield, Douglas G.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi. Umea Univ, Umea Plant Sci Ctr, Dept Ecol & Environm Sci, SE-90187 Umea, Sweden.;Uppsala Univ, Uppsala Multidisciplinary Ctr Adv Computat Sci, SE-75105 Uppsala, Sweden..
    Ingvarsson, Par K.
    Umea Univ, Umea Plant Sci Ctr, Dept Ecol & Environm Sci, SE-90187 Umea, Sweden..
    Natural Selection and Recombination Rate Variation Shape Nucleotide Polymorphism Across the Genomes of Three Related Populus Species2016Inngår i: Genetics, ISSN 0016-6731, E-ISSN 1943-2631, Vol. 202, nr 3, s. 1185-1200Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A central aim of evolutionary genomics is to identify the relative roles that various evolutionary forces have played in generating and shaping genetic variation within and among species. Here we use whole-genome resequencing data to characterize and compare genome-wide patterns of nucleotide polymorphism, site frequency spectrum, and population-scaled recombination rates in three species of Populus: Populus tremula, P. tremuloides, and P. trichocarpa. We find that P. tremuloides has the highest level of genome-wide variation, skewed allele frequencies, and population-scaled recombination rates, whereas P. trichocarpa harbors the lowest. Our findings highlight multiple lines of evidence suggesting that natural selection, due to both purifying and positive selection, has widely shaped patterns of nucleotide polymorphism at linked neutral sites in all three species. Differences in effective population sizes and rates of recombination largely explain the disparate magnitudes and signatures of linked selection that we observe among species. The present work provides the first phylogenetic comparative study on a genome-wide scale in forest trees. This information will also improve our ability to understand how various evolutionary forces have interacted to influence genome evolution among related species.

  • 1556.
    Wang, Jing
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Street, Nathaniel
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Umeå Plant Science Centre (UPSC). Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysiologisk botanik.
    Scofield, Douglas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. Department of Ecology and Genetics: Evolutionary Biology, Uppsala University, Uppsala; Uppsala Multidisciplinary Center for Advanced Computational Science, Uppsala University, Uppsala .
    Ingvarsson, Pär
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Natural Selection and Recombination Rate Variation Shape Nucleotide Polymorphism Across the Genomes of Three Related Populus Species2016Inngår i: Genetics, ISSN 0016-6731, E-ISSN 1943-2631, Vol. 202, nr 3, s. 1185-1200Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A central aim of evolutionary genomics is to identify the relative roles that various evolutionary forces have played in generating and shaping genetic variation within and among species. Here we use whole-genome resequencing data to characterize and compare genome-wide patterns of nucleotide polymorphism, site frequency spectrum, and population-scaled recombination rates in three species of PopulusPopulus tremulaP. tremuloides, and P. trichocarpa. We find that P. tremuloides has the highest level of genome-wide variation, skewed allele frequencies, and population-scaled recombination rates, whereas P. trichocarpa harbors the lowest. Our findings highlight multiple lines of evidence suggesting that natural selection, due to both purifying and positive selection, has widely shaped patterns of nucleotide polymorphism at linked neutral sites in all three species. Differences in effective population sizes and rates of recombination largely explain the disparate magnitudes and signatures of linked selection that we observe among species. The present work provides the first phylogenetic comparative study on a genome-wide scale in forest trees. This information will also improve our ability to understand how various evolutionary forces have interacted to influence genome evolution among related species.

  • 1557.
    Wang, Jing
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Street, Nathaniel
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysiologisk botanik.
    Scofield, Douglas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. Department of Ecology and Genetics: Evolutionary Biology, Uppsala University, Uppsala, Sweden; Uppsala Multidisciplinary Center for Advanced Computational Science, Uppsala University, Uppsala, Sweden.
    Ingvarsson, Pär
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Variation in linked selection and recombination drive genomic divergence during allopatric speciation of European and American aspens2016Inngår i: Molecular biology and evolution, ISSN 0737-4038, E-ISSN 1537-1719, Vol. 33, nr 7, s. 1754-1767Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Despite the global economic and ecological importance of forest trees, the genomic basis of differential adaptation and speciation in tree species is still poorly understood. Populus tremula and P. tremuloides are two of the most widespread tree species in the Northern Hemisphere. Using whole-genome re-sequencing data of 24 P. tremula and 22 P. tremuloidesindividuals, we find that the two species diverged ~2.2-3.1 million years ago, coinciding with the severing of the Bering land bridge and the onset of dramatic climatic oscillations during the Pleistocene. Both species have experienced substantial population expansions following long-term declines after species divergence. We detect widespread and heterogeneous genomic differentiation between species, and in accordance with the expectation of allopatric speciation, coalescent simulations suggest that neutral evolutionary processes can account for most of the observed patterns of genetic differentiation. However, there is an excess of regions exhibiting extreme differentiation relative to those expected under demographic simulations, which is indicative of the action of natural selection. Overall genetic differentiation is negatively associated with recombination rate in both species, providing strong support for a role of linked selection in generating the heterogeneous genomic landscape of differentiation between species. Finally, we identify a number of candidate regions and genes that may have been subject to positive and/or balancing selection during the speciation process.

  • 1558.
    Wang, Jing
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Tan, Biyue
    Street, Nathaniel
    Scofield, Douglas
    Ingvarsson, Pär
    The signatures of local adaptation at the genomic level in European aspen (Populus tremula)Manuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Although local adaptation plays a fundamental role in maintaining adaptive genetic variation as a response to changing environments, its underlying genetic mechanisms remains poorly understood. In this study, we integrate “top-down” and “bottom-up” approaches to search for genomic signatures of local adaptation in Populus tremula along a latitudinal gradient across Sweden. We find that a majority of single nucleotide polymorphisms (SNPs) (~95%) identified as being involved in local adaptation are tightly clustered in a single genomic region on chromosome 10. This region harbors the candidate gene FLOWERING LOCUS T2 (FT2) that has long been known to play important roles in the regulation of growth cessation and dormancy induction in perennial plants. Our results provide empirical evidence suggesting that in the context of high rates of gene flow, the genomic architecture of local adaptation tends to enrich for few large-effect and/or tightly clustered loci rather than many independent loci of small effect. The signatures of selection at the candidate region are mostly consistent with soft selective sweeps, where different adaptive haplotypes originating from standing genetic variation sweep to high frequency in different latitudinal regions. In particular, we identify a recent and strong selective sweep that is regionally restricted to the northernmost populations. This indicates that high-latitude populations likely have undergone a stronger adaptive response to the greater environmental perturbation during the post-glacial colonization of northern Scandinavia.

  • 1559.
    Wang, Mi
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Uebbing, Severin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Ellegren, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Allele-specific gene expression inferred by a Bayesian negative binomial approach indicates abundant cis-regulatory variation in natural flycatcher populationsManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Polymorphisms in cis-regulatory sequences can make the two alleles of a gene be expressed at different levels, providing a starting point for the evolution of divergence in gene expression. However, little is known about the genome-wide abundance of regulatory variation in natural populations. We performed RNA-seq of multiple tissues from population samples of two closely related flycatcher species and developed a Bayesian algorithm that maximises data usage by borrowing overdispersion estimates over the whole dataset and combines several SNPs per transcript to detect allele-specific expression (ASE). Of 2,576 transcripts analysed in collared flycatcher, ASE was detected in 185 (7.2%). A similar frequency was seen in the pied flycatcher but these frequencies are likely to be underestimates for several reasons. The proportion of ASE transcripts varied among tissues, being lowest in testis and highest in muscle. Often, ASE was seen in several tissues for particular gene-individual combinations. This is one of only very few large-scale studies investigating the incidence of ASE in the wild. The results suggest that genetic variation in regulatory sequences commonly affect gene expression in natural populations and that it provides a seedbed for phenotypic evolution via divergence in gene expression.

  • 1560.
    Ware, Jessica L.
    et al.
    Rutgers University, Newark, NJ, USA.
    Karlsson, Maria
    Lund University, Lund, Sweden.
    Sahlén, Göran
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS).
    Koch, Kamilla
    Johannes Gutenberg Universität Mainz, Mainz, Germany.
    Evolution of reproductive strategies in libellulid dragonflies (Odonata: Anisoptera)2012Inngår i: Organisms Diversity & Evolution, ISSN 1439-6092, E-ISSN 1618-1077, Vol. 12, nr 3, s. 313-323Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In Libellulidae, oocyte production has been assumed to be continuous, with periods of egg-laying interspersed with periods of resting/eating; however, recent work suggests that two types of oocyte production are common: either (a) continuous or (b) step-wise. These are mirrored in the arrangement of the ovarioles in the ovaries. Likewise, two types of mate-guarding behavior have been observed in Libellulidae: (1) non–contact guarding and (2) tandem guarding in which the male either hovers above the female or is physically attached to her during oviposition. Using molecular (mitochondrial and nuclear) data we explored the evolution of female reproductive traits, focusing on ovariole morphology, as well as guarding behavior, in Libellulidae. Continuous egg production appears to have evolved more than once, as have tandem and non-contact guarding. We discuss how the evolution of different ovariole types and guarding behavior may have been influenced by habitat instability, dispersal and crowded oviposition sites; thus, migratory behavior or habitat availability may have been the driving force of ovariole evolution.

  • 1561.
    Warshan, Denis
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Pederson, Eric
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Kim, Sea-Yong
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Pawlowski, Katharina
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Rasmussen, Ulla
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Shared and divergent genomic changes associated with the evolutionary transitions of Nostoc to a plant symbiontManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    The cyanobacteria belonging to the genus Nostoc comprise free-living strains but also facultative plant-symbionts. Symbiotic strains can enter into symbiosis with a taxonomically diverse range of host plants. Little is known about genomic changes associated with evolutionary transition of Nostoc from free-living to plant symbiont. Here we compared the genomes derived from eleven symbiotic Nostoc strains isolated from different host plants and infer phylogenetic relationships between strains. Phylogenetic reconstructions of 89 Nostocales showed that symbiotic Nostoc strains with a broad host range, entering epiphytic and intracellular or extracellular endophytic interactions, form a monophyletic clade indicating a common evolutionary history. A polyphyletic origin was found for Nostoc strains which enter only extracellular symbioses, suggesting that this trait was most likely gained several times in the evolution of the Nostocales. Facultative symbiotic Nostoc strains showed enriched functions in the transport and metabolism of organic sulfur, chemotaxis and motility, as well as the uptake of phosphate, amino acid and ammonium. The genomes of the intracellular clade differ from that of other Nostoc strains by a gain/enrichment of genes encoding proteins to generate L-methionine from sulfite and pathways for the degradation of the plant metabolites vanillin and vanillate, and of the macromolecule xylan present in plant cell-walls. These compounds could function as C sources for members of the intracellular clade. Molecular clock analysis suggested that the intracellular clade emerged ~600 million years ago, which would predate the origin of land plants. This suggest that intracellular cyanobacterial symbioses may have even predated the emergence of extant terrestrial plants.

  • 1562.
    Warsi, Omar M.
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för medicinsk biokemi och mikrobiologi. SUNY Stony Brook, Dept Ecol & Evolut, Stony Brook, NY 11794 USA.
    Dykhuizen, Daniel E.
    SUNY Stony Brook, Dept Ecol & Evolut, Stony Brook, NY 11794 USA..
    Evolutionary implications of Liebig's law of the minimum: Selection under low concentrations of two nonsubstitutable nutrients2017Inngår i: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 7, nr 14, s. 5296-5309Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Interactions between different axes of an organism's niche determine the evolutionary trajectory of a population. An extreme case of these interactions is predicted from ecological theory in Liebig's law of the minimum. This law states that in environments where multiple nutrients are in relatively low concentrations, only one nutrient will affect the growth of the organism. This implies that the evolutionary response of the population would be dictated by the most growth-limiting nutrient. Alternatively, it is possible that an initial adaptation to the most limiting nutrient results in other nutrients present in low concentration affecting the evolutionary dynamics of the population. To test these hypotheses, we conducted twelve evolution experiments in chemostats using Escherichia coli populations: four under nitrogen limitation, four under magnesium limitation, and four in which both nitrogen and magnesium are in low concentrations. In the last environment, only magnesium seems to limit growth (Low Nitrogen Magnesium Limited environment, LNML). We observe a decrease in nitrogen concentration in the LNML environment over the course of our evolution experiment indicating that nitrogen might become limiting in these environments. Genetic reconstruction results show that clones adapted to magnesium limitation have genes involved in nitrogen starvation, that is, glnG (nitrogen starvation transcriptional regulator) and amtB (transport protein) to be upregulated only in the LNML environment as compared to magnesium-limiting environments. Together, our results highlights that in low-nutrient environments, adaptation to the growth-limiting nutrient results in other nutrients at low concentrations to play a role in the evolutionary dynamics of the population.

  • 1563. Watson, P J
    et al.
    Arnqvist, Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Stallmann, R R
    Sexual conflict and the energetic costs of mating and mate choice in water striders1998Inngår i: American Naturalist, ISSN 0003-0147, E-ISSN 1537-5323, Vol. 151, nr 1, s. 46-58Artikkel i tidsskrift (Fagfellevurdert)
  • 1564. Wedin, Mats
    et al.
    Westberg, Martin
    Crewe, Anna T
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Tehler, Anders
    Purvis, O William
    Species delimitation and evolution of metal bioaccumulation in the lichenized Acarospora smaragdula (Ascomycota, Fungi) complex2009Inngår i: Cladistics, ISSN 0748-3007, E-ISSN 1096-0031, Vol. 25, nr 2, s. 161-172Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The crustose lichenized fungi in the Acarosporaceae are splendid examples of organisms managing to survive in extremely harsh environments, such as highly mineralized rocks and low-pH habitats. Some representatives of the Acarospora smaragdula complex are known to accumulate substantial amounts of potentially toxic metals including iron and copper, resulting in populations with highly divergent coloration and morphology. These populations have often been treated as distinct species by lichen taxonomists. Parsimony and parsimony jackknifing analyses of beta-tubulin, nuclear ITS rDNA, and mtSSU rDNA sequence data sets was used to investigate the evolution of iron and copper accumulation and the production of the secondary compound norstictic acid in populations within the A. smaragdula species complex in Sweden, with additional samples mainly from Norway and the UK. Phylogenetic species recognition (concordance of single-gene phylogenies) was used to investigate species delimitations. Seven species are recognized in the complex. Atypically green, copper-accumulating samples, often given species rank, do not form a distinct group but are nested within A. smaragdula s. str., indicating that this ability is widespread in this species. Rust-coloured, iron-accumulating samples form two well supported separate groups, indicating that two morphologically distinct, obligate, iron-accumulating species are present, but facultatively iron-accumulating populations occur in at least one additional species. Norstictic acid, sometimes claimed to characterize the whole A. smaragdula complex, is only present in A. smaragdula s. str. The evolutionary significance of metal accumulation in Acarospora is discussed, as is the significance of our results for the application of phylogenetic species recognition/gene tree concordance-based species recognition, and DNA barcoding.

  • 1565. Wedin, Mats
    et al.
    Wiklund, Elisabeth
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Jorgensen, Per Magnus
    Ekman, Stefan
    Slippery when wet: phylogeny and character evolution in the gelatinous cyanobacterial lichens (Peltigerales, Ascomycetes)2009Inngår i: Molecular Phylogenetics and Evolution, ISSN 1055-7903, E-ISSN 1095-9513, Vol. 53, nr 3, s. 862-871Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Many lichen fungi form symbioses with filamentous Nostoc cyanobacteria, which cause the lichen to swell and become extremely gelatinous when moist. Within the Lecanoromycetes, such gelatinous lichens are today mainly classified in the Collemataceae (Peltigerales, Ascomycota). We performed Bayesian MCMC, maximum likelihood, and maximum parsimony analyses of three independent markers (mtSSU rDNA, nuLSU rDNA, and RPB1), to improve our understanding of the phylogeny and classification in the Peltigerales, as well as the evolution of morphological characters that have been used for classification purposes in this group. The Collemataceae and the non-gelatinous Parmariaceae are paraphyletic but can be re-circumscribed as monophyletic if Leciophysma, Physma, Ramalodium and Staurolemma are transferred to the Parmariaceae. The gelatinous taxa transferred to the Parmariaceae deviate from other Collemataceae in having simple ascospores, and several also have a ring-shaped exciple as in other Pannariaceae, rather than the disc-shaped exciple found in the typical Collemataceae. Both Collema and Leptogium are non-monophyletic. The re-circumscribed Collemataceae shares a distinct ascus type with the sister group Placynthiaceae and the Coccocarpiaceae, whereas Parmariaceae includes a variety of structures. All Parmariaceae have one-celled ascospores, whereas all Collemataceae have two- or multi-celled spores. Reconstructions of the number of character state transformations in exciple structure, thallus gelatinosity, and ascus apex structure indicate that the number of transformations is distinctly higher than the minimum possible. Most state transformations in the exciple took place from a ring-shaped to a disc-shaped exciple. Depending on the reconstruction method, most or all transformations in thallus structure took place from a non-gelatinous to a gelatinous thallus. Gains and losses of internal structures in the ascus apex account for all or a vast majority of the number of transformations in the ascus, whereas direct transformations between asci with internal structures appear to have been rare.

  • 1566. Weeks, Andrew R.
    et al.
    Sgro, Carla M.
    Young, Andrew G.
    Frankham, Richard
    Mitchell, Nicki J.
    Miller, Kim A.
    Byrne, Margaret
    Coates, David J.
    Eldridge, Mark D. B.
    Sunnucks, Paul
    Breed, Martin F.
    Australian Centre for Evolutionary Biology and Biodiversity, and School of Earth and Environmental Science, University of Adelaide.
    James, Elizabeth A.
    Hoffmann, Ary A.
    Assessing the benefits and risks of translocations in changing environments: a genetic perspective2011Inngår i: Evolutionary Applications, ISSN 1752-4571, E-ISSN 1752-4571, Vol. 4, nr 6, s. 709-725Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Translocations are being increasingly proposed as a way of conserving biodiversity, particularly in the management of threatened and keystone species, with the aims of maintaining biodiversity and ecosystem function under the combined pressures of habitat fragmentation and climate change. Evolutionary genetic considerations should be an important part of translocation strategies, but there is often confusion about concepts and goals. Here, we provide a classification of translocations based on specific genetic goals for both threatened species and ecological restoration, separating targets based on ‘genetic rescue’ of current population fitness from those focused on maintaining adaptive potential. We then provide a framework for assessing the genetic benefits and risks associated with translocations and provide guidelines for managers focused on conserving biodiversity and evolutionary processes. Case studies are developed to illustrate the framework.

  • 1567. Wellenreuther, M.
    et al.
    Rosenquist, H.
    Jaksons, P.
    Larson, Keith W
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Local adaptation along an environmental cline in a species with an inversion polymorphism2017Inngår i: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 30, nr 6, s. 1068-1077Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Polymorphic inversions are ubiquitous across the animal kingdom and are frequently associated with clines in inversion frequencies across environmental gradients. Such clines are thought to result from selection favouring local adaptation; however, empirical tests are scarce. The seaweed fly Coelopa frigida has an alpha/beta inversion polymorphism, and previous work demonstrated that the alpha inversion frequency declines from the North Sea to the Baltic Sea and is correlated with changes in tidal range, salinity, algal composition and wrackbed stability. Here, we explicitly test the hypothesis that populations of C. frigida along this cline are locally adapted by conducting a reciprocal transplant experiment of four populations along this cline to quantify survival. We found that survival varied significantly across treatments and detected a significant Location x Substrate interaction, indicating local adaptation. Survival models showed that flies from locations at both extremes had highest survival on their native substrates, demonstrating that local adaptation is present at the extremes of the cline. Survival at the two intermediate locations was, however, not elevated at the native substrates, suggesting that gene flow in intermediate habitats may override selection. Together, our results support the notion that population extremes of species with polymorphic inversions are often locally adapted, even when spatially close, consistent with the growing view that inversions can have direct and strong effects on the fitness of species.

  • 1568. Wellenreuther, Maren
    et al.
    Larson, Keith W.
    Evolutionary Ecology Unit, Department of Biology, Ecology Building, Lund University, SE-223 62 Lund, Sweden.
    Svensson, Erik I.
    Climatic niche divergence or conservatism?: Environmental niches and range limits in ecologically similar damselflies2012Inngår i: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, Vol. 93, nr 6, s. 1353-1366Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The factors that determine species' range limits are of central interest to biologists. One particularly interesting group comprises odonates (dragonflies and damselflies), which show large differences in secondary sexual traits and respond quickly to climatic factors, but often have minor interspecific niche differences, challenging models of niche-based species coexistence. We quantified the environmental niches at two geographic scales to understand the ecological causes of northern range limits and the coexistence of two congeneric damselflies (Calopteryx splendens and C. virgo). Using environmental niche modeling, we quantified niche divergence first across the whole geographic range in Fennoscandia, and second only in the sympatric part of this range. We found evidence for interspecific divergence along the environmental axes of temperature and precipitation across the northern range in Fennoscandia, suggesting that adaptation to colder and wetter climate might have allowed C. virgo to expand farther north than C. splendens. However, in the sympatric zone in southern Fennoscandia we found only negligible and nonsignificant niche differences. Minor niche differences in sympatry lead to frequent encounters and intense interspecific sexual interactions at the local scale of populations. Nevertheless, niche differences across Fennoscandia suggest that species differences in physiological tolerances limit range expansions northward, and that current and future climate could have large effects on the distributional ranges of these and ecologically similar insects.

  • 1569.
    Wennersten, Lena
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för naturvetenskap, NV.
    Population-level consequences of variation2012Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Consequences of within population variation have recently attracted an increased interest in evolutionary ecology research. Theoretical models suggest important population-level consequences, but many of these predictions still remain to be tested. These issues are important for a deepened understanding of population performances and persistence, especially in a world characterized by rapid fragmentation of natural habitats and other environmental changes.

    I review theoretical models of consequences from intra population genetic and phenotypic variation. I find that more variable populations are predicted to be characterized by broader resource use, reduced intraspecific competition, reduced vulnerability to environmental changes, more stable population dynamics, higher invasive potential, enhanced colonization and establishment success, larger distribution ranges, higher evolvability, higher productivity, faster population growth rate, decreased extinction risk, and higher speciation rate, compared with less variable populations.

    To test some of these predictions I performed experiments and compared how different degree of colour polymorphism influences predation risk and establishment success in small groups. My comparisons of predation risk in mono- and polymorphic artificial prey populations showed that the risk of being eaten by birds does not only depend on the coloration of the individual prey item itself, but also on the coloration of the other members of the group. Two experiments on establishment success in small founder groups of

    Tetrix subulata pygmy grasshoppers with different degree of colour morph diversity show that establishment success increases with higher degree of diversity, both under controlled conditions in outdoor enclosures and in the wild. These findings may be important for re-stocking of declining populations or re-introductions of locally extinct populations in conservation biology projects.

    I report on remarkably rapid evolutionary shifts in colour morph frequencies in response to the changed environmental conditions in replicated natural populations of pygmy grasshoppers in fire ravaged areas. This finding

    1

    illustrates the high adaptive potential in a polymorphic species, and indicates the importance of preserved within-species diversity for evolutionary rescue.

    Finally, I review if theoretical predictions are supported by other published empirical tests and find strong support for the predictions that more variable groups benefit from reduced vulnerability to environmental changes, reduced population fluctuations and extinction risk, larger distribution ranges, and higher colonization or establishment success.

    In conclusion, my thesis illustrates how within-population variation influences ecological and evolutionary performances of populations both in the short and long term. As such, it emphasizes the need for conservation of biodiversity also within populations.

  • 1570.
    Wennersten, Lena
    et al.
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Forsman, Anders
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Does colour polymorphism enhance survival of prey populations?2009Inngår i: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 276, nr 1665, s. 2187-2194Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    That colour polymorphism may protect prey populations from predation is an old but rarely tested hypothesis. We examine whether colour polymorphic populations of prey exposed to avian predators in an ecologically valid visual context were exposed to increased extinction risk compared with monomorphic populations. We made 2976 artificial pastry prey, resembling Lepidoptera larvae, in four different colours and presented them in 124 monomorphic and 124 tetramorphic populations on tree trunks and branches such that they would be exposed to predation by free-living birds, and monitored their 'survival'. Among monomorphic populations, there was a significant effect of prey coloration on survival, confirming that coloration influenced susceptibility to visually oriented predators. Survival of polymorphic populations was inferior to that of monomorphic green populations, but did not differ significantly from monomorphic brown, yellow or red populations. Differences in survival within polymorphic populations paralleled those seen among monomorphic populations; the red morph most frequently went extinct first and the green morph most frequently survived the longest. Our findings do not support the traditional protective polymorphism hypothesis and are in conflict with those of earlier studies. As a possible explanation to our findings, we offer a competing 'giveaway cue' hypothesis: that polymorphic populations may include one morph that attracts the attention of predators and that polymorphic populations therefore may suffer increased predation compared with some monomorphic populations.

  • 1571.
    Wennersten, Lena
    et al.
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för naturvetenskap, NV.
    Forsman, Anders
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för naturvetenskap, NV.
    Population-level consequences of polymorphism, plasticity and randomized phenotype switching: a review of predictions2012Inngår i: Biological Reviews, ISSN 1464-7931, E-ISSN 1469-185X, Vol. 87, nr 3, s. 756-767Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    The consequences of among-individual phenotypic variation for the performance and ecological success of populations and species has attracted growing interest in recent years. Earlier reviews of this field typically address the consequences for population processes of one specific source of variation (plasticity or polymorphism), or consider one specific aspect of population performance, such as rate of speciation. Here we take a broader approach and study earlier reviews in order to summarize and compare predictions regarding several population-level consequences of phenotypic variation stemming from genetic polymorphism, developmental plasticity or randomized phenotype switching. Unravelling cause-dependent consequences of variation may increase our ability to understand the ecological dynamics of natural populations and communities, develop more informed management plans for protection of biodiversity, suggest possible routes to increased productivity and yield in natural and managed biological systems, and resolve inconsistencies in patterns and results seen in studies of different model systems. We find an overall agreement regarding the effects of higher levels of phenotypic variation generated by different sources, but also some differences between fine-grained and coarse-grained environments, modular and unitary organisms, mobile and sessile organisms, and between flexible and fixed traits. We propose ways to test the predictions and identify issues where current knowledge is limited and future lines of investigation promise to provide important novel insights.

  • 1572.
    Wennersten, Lena
    et al.
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Forsman, Anders
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Strong support for predicted population-level consequences of diversity: a review of exeperimental and comparative studiesManuskript (preprint) (Annet vitenskapelig)
  • 1573.
    Wennersten, Lena
    et al.
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för naturvetenskap, NV.
    Karpestam, Einat
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för naturvetenskap, NV.
    Forsman, Anders
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för naturvetenskap, NV.
    Phenotype manipulation influences microhabitat choice in pygmy grasshoppers2012Inngår i: Current Zoology, ISSN 1674-5507, Vol. 58, nr 3, s. 392-400Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The matching habitat choice hypothesis posits that individuals actively choose those microhabitats that best match their specificphenotype to maximize fitness. Despite the profound implications, matching habitat choice has not been unequivocally demonstrated. Weconducted two experiments to examine the impact of pigmentation pattern in the color polymorphic pygmy grasshopper Tetrix subulata onhabitat choice in a laboratory thermal mosaic arena. We found no behavioral differences in the thermal mosaic among pygmy grasshoppersbelonging to either pale, intermediate or dark natural color morphs. However, after manipulating the grasshoppers’ phenotype, the utilizationthrough time of warmer and colder parts of the arena was different for black-painted and white-painted individuals. White-paintedindividuals used warmer parts of the arena, at least during the initial stage of the experiment. We conclude that microhabitat choicerepresents a form of behavioural plasticity. Thus, even if the choice itself is flexible and not genetically determined, it can still lead to spatialgenetic structure in the population because the phenotypes themselves may be genetically mediated

  • 1574.
    Werdelin, Lars
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Jaw geometry and molar morphology in marsupial carnivores: analysis of a constraint and its macroevolutionary consequences1987Inngår i: Paleobiology, ISSN 0094-8373, E-ISSN 1938-5331, Vol. 13, s. 342-350Artikkel i tidsskrift (Fagfellevurdert)
  • 1575.
    Werdelin, Lars
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    King of beasts2013Inngår i: Scientific American, nr 11, s. 34-39Artikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
  • 1576.
    Werdelin, Lars
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Människans evolution2016Inngår i: Fauna och flora : populär tidskrift för biologi, ISSN 0014-8903, Vol. 111, s. 2-10Artikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
  • 1577.
    Werdelin, Lars
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Phylogenies, fossils and evolutionary studies1993Inngår i: Quaternary International, ISSN 1040-6182, E-ISSN 1873-4553, Vol. 19, s. 109-116Artikkel i tidsskrift (Fagfellevurdert)
  • 1578.
    Werdelin, Lars
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Revealing the maternal demographic history of Panthera leo using ancient DNA and a spatially explicit genealogical analysis2014Inngår i: BMC Evolutionary Biology, Vol. 14, nr 70Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

     Background: Understanding the demographic history of a population is critical to conservation and to our broader understanding of evolutionary processes. For many tropical large mammals, however, this aim is confounded by the absence of fossil material and by the misleading signal obtained from genetic data of recently fragmented and isolated populations. This is particularly true for the lion which as a consequence of millennia of human persecution, has large gaps in its natural distribution and several recently extinct populations.

    Results: We sequenced mitochondrial DNA from museum-preserved individuals, including the extinct Barbary lion (Panthera leo leo) and Iranian lion (P. l. persica), as well as lions from West and Central Africa. We added these to a broader sample of lion sequences, resulting in a data set spanning the historical range of lions. Our Bayesian phylogeographical analyses provide evidence for highly supported, reciprocally monophyletic lion clades. Using a molecular clock, we estimated that recent lion lineages began to diverge in the Late Pleistocene. Expanding equatorial rainforest probably separated lions in South and East Africa from other populations. West African lions then expanded into Central Africa during periods of rainforest contraction. Lastly, we found evidence of two separate incursions into Asia from North Africa, first into India and later into the Middle East.

    Conclusions: We have identified deep, well-supported splits within the mitochondrial phylogeny of African lions, arguing for recognition of some regional populations as worthy of independent conservation. More morphological and nuclear DNA data are now needed to test these subdivisions.

  • 1579.
    Werdelin, Lars
    et al.
    Department of Palaeozoology, Swedish Museum of Natural History.
    Dehghani, Reihaneh
    Department of Palaeozoology, Swedish Museum of Natural History.
    Carnivora2011Inngår i: Paleontology and Geology of Laetoli: Human Evolution in Context: Volume 2: Fossil Hominins and the Associated Fauna / [ed] Terry Harrison, Dordrecht: Springer Netherlands, 2011, s. 189-232Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    This paper reviews the extensive carnivoran fauna of Laetoli on the basis of collections housed in Berlin, London, Nairobi, and Dar es Salaam. Members of the Carnivora are known from both the Lower and Upper Laetolil Beds, as well as from the Upper Ndolanya Beds. Of these, the Upper Laetolil Beds are best sampled, and the material includes a minimum of 28 species of Carnivora (four Canidae, three Mustelidae, three Viverridae, six Herpestidae, five Hyaenidae, and seven Felidae). Many of the smaller Carnivora species include complete or partial skeletons and whole, undamaged crania, suggesting rapid burial and absence of trampling and other taphonomic processes that severely affected the more fragmentary larger Carnivora. The Upper Ndolanya Beds Carnivora are preserved in a similar fashion. This stratigraphic unit includes nine to ten species (one Mustelidae, two Herpestidae, one or two Hyaenidae, and five Felidae). All of these are also known from the Upper Laetolil Beds. The Lower Laetolil Beds are less well sampled, with only four species of Carnivora (one Mustelidae, one Herpestidae, and two Hyaenidae). Of these, the mustelid and one hyenid are unique to this stratigraphic unit, while one hyenid is shared with the Upper Laetolil Beds and the herpestid with both the Upper Laetolil Beds and the Upper Ndolanya Beds. Three of the Lower Laetolil Beds Carnivora (all except the herpestid) are partial skeletons, suggesting different depositional or taphonomic conditions at that time, while the presence of an otter in the Lower Laetolil Beds indicates the presence of a large, permanent body of water in the vicinity.

  • 1580.
    Werdelin, Lars
    et al.
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Lewis, Margaret E.
    A contextual review of the Carnivora of Kanapoi2017Inngår i: Journal of Human Evolution, ISSN 0047-2484, E-ISSN 1095-8606Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Early Pliocene is a crucial time period in carnivoran evolution. Holarctic carnivoran faunas suffered a turnover event at the Miocene-Pliocene boundary. This event is also observed in Africa but its onset is later and the process more drawn-out. Kanapoi is one of the earliest faunas in Africa to show evidence of a fauna that is more typical Pliocene than Miocene in character. The taxa recovered from Kanapoi are: Torolutra sp., Enhydriodon (2 species), Genetta sp., Helogale sp., Homotherium sp., Dinofelis petteri, Felis sp., and Parahyaena howelli. Analysis of the broader carnivoran context of which Kanapoi is an example shows that all these taxa are characteristic of Plio-Pleistocene African faunas, rather than Miocene ones. While some are still extant and some went extinct in the Early Pleistocene, P. howelli is unique in both originating and going extinct in the Early Pliocene.

  • 1581.
    Werdelin, Lars
    et al.
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Nilsonne, Åsa
    The evolution of the scrotum and testicular descent: a phylogenetic view1999Inngår i: Journal of Theoretical Biology, ISSN 0022-5193, E-ISSN 1095-8541, Vol. 196, s. 61-72Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The adaptive significance of the scrotum and the evolution of the descent of the testicles and epididymis have been a focus of interest among biologists for a long time. In this paper we use three anatomical character states of the scrotum and descensus: (1) testicles descended and scrotal; (2) testicles descended but ascrotal; (3) testicles not descended (testicondy#). These states are then mapped on an up to date phylogeny of the Mammalia. Three main points arise out of this mapping procedure: (1) the presence of a scrotum is either primitive in extant Mammalia or primitive within eutherian mammals except Insectivora; (2) evolution has generally proceeded from a scrotal condition to progressively more ascrotal; (3) loss of testicular descensus is less common in mammalian evolution than is loss of the scrotum. In the light of these findings we discuss some current hypotheses regarding the origin and evolution of the scrotum. We find that these are all incomplete in so far as it is not the presence of the scrotum in various mammal groups that requires explaining. Instead, it is the reverse process, why the scrotum has been lost in so many groups, that should be explained. We suggest that the scrotum may have evolved before the origin of mammals, in concert with the evolution of endothermy in the mammalian lineage, and that the scrotum has been lost in many groups because descensus in many respects is a costly process that will be lost in mammal lineages as soon as an alternative solution to the problem of the temperature sensitivity of spermatogenesis is available.

  • 1582.
    Wheat, Christopher W.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Wahlberg, Niklas
    Phylogenomic Insights into the Cambrian Explosion, the Colonization of Land and the Evolution of Flight in Arthropoda2013Inngår i: Systematic Biology, ISSN 1063-5157, E-ISSN 1076-836X, Vol. 62, nr 1, s. 93-109Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The timing of the origin of arthropods in relation to the Cambrian explosion is still controversial, as are the timing of other arthropod macroevolutionary events such as the colonization of land and the evolution of flight. Here we assess the power of a phylogenomic approach to shed light on these major events in the evolutionary history of life on earth. Analyzing a large phylogenomic dataset (122 taxa, 62 genes) with a Bayesian-relaxed molecular clock, we simultaneously reconstructed the phylogenetic relationships and the absolute times of divergences among the arthropods. Simulations were used to test whether our analysis could distinguish between alternative Cambrian explosion scenarios with increasing levels of autocorrelated rate variation. Our analyses support previous phylogenomic hypotheses and simulations indicate a Precambrian origin of the arthropods. Our results provide insights into the 3 independent colonizations of land by arthropods and suggest that evolution of insect wings happened much earlier than the fossil record indicates, with flight evolving during a period of increasing oxygen levels and impressively large forests. These and other findings provide a foundation for macroevolutionary and comparative genomic study of Arthropoda.

  • 1583.
    Whelan, Simon
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Allen, James E.
    Blackburne, Benjamin P.
    Talavera, David
    ModelOMatic: Fast and Automated Model Selection between RY, Nucleotide, Amino Acid, and Codon Substitution Models2015Inngår i: Systematic Biology, ISSN 1063-5157, E-ISSN 1076-836X, Vol. 64, nr 1, s. 42-55Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Molecular phylogenetics is a powerful tool for inferring both the process and pattern of evolution from genomic sequence data. Statistical approaches, such as maximum likelihood and Bayesian inference, are now established as the preferred methods of inference. The choice of models that a researcher uses for inference is of critical importance, and there are established methods for model selection conditioned on a particular type of data, such as nucleotides, amino acids, or codons. A major limitation of existing model selection approaches is that they can only compare models acting upon a single type of data. Here, we extend model selection to allow comparisons between models describing different types of data by introducing the idea of adapter functions, which project aggregated models onto the originally observed sequence data. These projections are implemented in the program ModelOMatic and used to perform model selection on 3722 families from the PANDIT database, 68 genes from an arthropod phylogenomic data set, and 248 genes from a vertebrate phylogenomic data set. For the PANDIT and arthropod data, we find that amino acid models are selected for the overwhelming majority of alignments; with progressively smaller numbers of alignments selecting codon and nucleotide models, and no families selecting RY-based models. In contrast, nearly all alignments from the vertebrate data set select codon-based models. The sequence divergence, the number of sequences, and the degree of selection acting upon the protein sequences may contribute to explaining this variation in model selection. Our ModelOMatic program is fast, with most families from PANDIT taking fewer than 150 s to complete, and should therefore be easily incorporated into existing phylogenetic pipelines. ModelOMatic is available at https://code.google.com/p/modelomatic/.

  • 1584.
    Whittle, Carrie A.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Sun, Yu
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Johannesson, Hanna
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Dynamics of transcriptome evolution in the model eukaryote Neurospora2014Inngår i: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 27, nr 6, s. 1125-1135Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Mounting evidence indicates that changes in the transcriptome contribute significantly to the phenotypic differentiation of closely related species. Nonetheless, further genome-wide studies, spanning a broad range of organisms, are needed to decipher the factors driving transcriptome evolution. The model Neurospora (Ascomycota) comprises a simple system for empirically studying the evolutionary dynamics of the transcriptome. Here, we studied the evolution of gene expression in Neurospora crassa and Neurospora tetrasperma and show that patterns of transcriptome evolution are connected to genome evolution, tissue type and sexual identity (mating types, mat A and mat a) in these eukaryotes. Based on the comparisons of inter- and intraspecies expression divergence, our data reveal that rapid expression divergence is more apt to occur in sexual/female (SF) than vegetative/male (VM) tissues. In addition, interspecies gene expression and protein sequence divergence were strongly correlated for SF, but not VM, tissue. A correlation between transcriptome and protein evolution parallels findings from certain animals, but not yeast, and add support for the theory that expression evolution differs fundamentally among multicellular and unicellular eukaryotes. Finally, we found that sexual identity in these hermaphroditic Neurospora species is connected to interspecies expression divergence in a tissue-dependent manner: rapid divergence occurred for mat A- and mat a-biased genes from SF and VM tissues, respectively. Based on these findings, it is hypothesized that rapid interspecies transcriptome evolution is shifting the mating types of Neurospora towards distinct female and male phenotypes, that is, sexual dimorphism.

  • 1585.
    Whittle, Carrie A.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Sun, Yu
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Johannesson, Hanna
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Evolution of Synonymous Codon Usage in Neurospora tetrasperma and Neurospora discreta2011Inngår i: Genome Biology and Evolution, ISSN 1759-6653, E-ISSN 1759-6653, Vol. 3, s. 332-343Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Neurospora comprises a primary model system for the study of fungal genetics and biology. In spite of this, little is known about genome evolution in Neurospora. For example, the evolution of synonymous codon usage is largely unknown in this genus. In the present investigation, we conducted a comprehensive analysis of synonymous codon usage and its relationship to gene expression and gene length (GL) in Neurospora tetrasperma and Neurospora discreta. For our analysis, we examined codon usage among 2,079 genes per organism and assessed gene expression using large-scale expressed sequenced tag (EST) data sets (279,323 and 453,559 ESTs for N. tetrasperma and N. discreta, respectively). Data on relative synonymous codon usage revealed 24 codons (and two putative codons) that are more frequently used in genes with high than with low expression and thus were defined as optimal codons. Although codon-usage bias was highly correlated with gene expression, it was independent of selectively neutral base composition (introns); thus demonstrating that translational selection drives synonymous codon usage in these genomes. We also report that GL (coding sequences [CDS]) was inversely associated with optimal codon usage at each gene expression level, with highly expressed short genes having the greatest frequency of optimal codons. Optimal codon frequency was moderately higher in N. tetrasperma than in N. discreta, which might be due to variation in selective pressures and/or mating systems.

  • 1586.
    Wickman, Jonas
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för matematik och matematisk statistik.
    Diehl, Sebastian
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Blasius, Bernd
    Klausmeier, Christopher A.
    Ryabov, Alexey B.
    Brännström, Åke
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för matematik och matematisk statistik.
    Determining Selection across Heterogeneous Landscapes: A Perturbation-Based Method and Its Application to Modeling Evolution in Space2017Inngår i: American Naturalist, ISSN 0003-0147, E-ISSN 1537-5323, Vol. 189, nr 4, s. 381-395Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Spatial structure can decisively influence the way evolutionary processes unfold. To date, several methods have been used to study evolution in spatial systems, including population genetics, quantitative genetics, moment-closure approximations, and individual-based models. Here we extend the study of spatial evolutionary dynamics to eco-evolutionary models based on reaction-diffusion equations and adaptive dynamics. Specifically, we derive expressions for the strength of directional and stabilizing/disruptive selection that apply both in continuous space and to metacommunities with symmetrical dispersal between patches. For directional selection on a quantitative trait, this yields a way to integrate local directional selection across space and determine whether the trait value will increase or decrease. The robustness of this prediction is validated against quantitative genetics. For stabilizing/disruptive selection, we show that spatial heterogeneity always contributes to disruptive selection and hence always promotes evolutionary branching. The expression for directional selection is numerically very efficient and hence lends itself to simulation studies of evolutionary community assembly. We illustrate the application and utility of the expressions for this purpose with two examples of the evolution of resource utilization. Finally, we outline the domain of applicability of reaction-diffusion equations as a modeling framework and discuss their limitations.

  • 1587.
    Wikström, Niklas
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik. Stockholms universitet, Naturvetenskapliga fakulteten, Bergianska botaniska trädgården (tills m Kungl. Vetenskapsakademien).
    Neupane, Suman
    Karehed, Jesper
    Motley, Timothy J.
    Bremer, Birgitta
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik. Stockholms universitet, Naturvetenskapliga fakulteten, Bergianska botaniska trädgården (tills m Kungl. Vetenskapsakademien).
    Phylogeny of Hedyotis L. (Rubiaceae Spermacoceae): Redefining a complex Asian-Pacific assemblage2013Inngår i: Taxon, ISSN 0040-0262, E-ISSN 1996-8175, Vol. 62, nr 2, s. 357-374Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The genus Hedyotis (Rubiaceae: Spermacoceae) has long served as a repository for tropical herbaceous species that do not fit readily into other genera. Circumscribed broadly the genus becomes a highly heterogeneous assembly, but relationships of Hedyotis have been difficult to resolve and it has proven very difficult to circumscribe the genus in a more narrow sense. Here we present Bayesian phylogenetic analyses of Hedyotis using plastid (rps16, petD) and nuclear (ITS, ETS) sequence data to resolve monophyletic lineages, to test former taxonomic hypotheses, and to revise the taxa within a well-supported evolutionary framework. Four hundred and sixty-seven sequences representing 129 accessions, never previously included in any phylogenetic analyses, are newly reported. Hedyotis, as previously circumscribed, is polyphyletic, but all investigated species, except for Hedyotis coronaria, are resolved in one of three well-supported monophyletic groups. The largest clade includes all investigated species of Hedyotis from the Indian subcontinent as well as three groups of species with primarily Chinese distributions. The type species of Hedyotis (H. fruticosa) is resolved with the Indian subcontinent species and following previous suggestions this group is referred to as Hedyotis s.str. Species currently recognized under the generic names Metabolos and Pleiocraterium are resolved in Hedyotis s.str. The second-largest group comprises a series of smaller, but well-supported, clades including the Leptopetalum clade, the genus Kadua, an unnamed group distributed in Asia and the Pacific, and a large Asian group referred to here as the ExallagelDimetia clade. The third group includes a few SE Asian Hedyotis, as well as all investigated species of the genus Neanotis. Hedyotis coronaria is not closely related to other species from Asia and is resolved with Spern2acoce hispida. The analyses indicate that diplophragmous capsules and fruticosa-type seeds occur outside of Hedyotis s.str., and several species suggested to have these features are resolved in the ExallagelDimetia clade. Species suggested to have indehiscent capsules, a feature used by Bremekamp to characterize the genus Exallage, are also resolved in both the ExallagelDimetia clade and in Hedyotis s.str., but a close examination indicates that the capsules are not truly indehiscent in the Hedyotis s.str. species. One species of Metabolos and one species of Pleiocraterium are given new species names, and one species of Pleiocrateriam is transferred to Hedyotis and three species of Hedyotis are transferred to Neanotis.

  • 1588.
    Williams, Laura
    et al.
    Univ Kaiserslautern, Plant Ecol & Systemat, Inst Biol, Kaiserslautern, Germany..
    Colesie, Claudia
    Univ Kaiserslautern, Plant Ecol & Systemat, Inst Biol, Kaiserslautern, Germany..
    Ullmann, Anna
    Univ Kaiserslautern, Plant Ecol & Systemat, Inst Biol, Kaiserslautern, Germany..
    Westberg, Martin
    Uppsala universitet, Enheten för musik och museer, Evolutionsmuseet.
    Wedin, Mats
    Swedish Museum Nat Hist, Dept Bot, Stockholm, Sweden..
    Büdel, Burkhard
    Univ Kaiserslautern, Plant Ecol & Systemat, Inst Biol, Kaiserslautern, Germany..
    Lichen acclimation to changing environments: Photobiont switching vs. climate-specific uniqueness in Psora decipiens2017Inngår i: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 7, nr 8, s. 2560-2574Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Unraveling the complex relationship between lichen fungal and algal partners has been crucial in understanding lichen dispersal capacity, evolutionary processes, and responses in the face of environmental change. However, lichen symbiosis remains enigmatic, including the ability of a single fungal partner to associate with various algal partners. Psora decipiens is a characteristic lichen of biological soil crusts (BSCs), across semi-arid, temperate, and alpine biomes, which are particularly susceptible to habitat loss and climate change. The high levels of morphological variation found across the range of Psora decipiens may contribute to its ability to withstand environmental change. To investigate Psora decipiens acclimation potential, individuals were transplanted between four climatically distinct sites across a European latitudinal gradient for 2years. The effect of treatment was investigated through a morphological examination using light and SEM microscopy; 26S rDNA and rbcL gene analysis assessed site-specific relationships and lichen acclimation through photobiont switching. Initial analysis revealed that many samples had lost their algal layers. Although new growth was often determined, the algae were frequently found to have died without evidence of a new photobiont being incorporated into the thallus. Mycobiont analysis investigated diversity and determined that new growth was a part of the transplant, thus, revealing that four distinct fungal clades, closely linked to site, exist. Additionally, P.decipiens was found to associate with the green algal genus Myrmecia, with only two genetically distinct clades between the four sites. Our investigation has suggested that P.decipiens cannot acclimate to the substantial climatic variability across its environmental range. Additionally, the different geographical areas are home to genetically distinct and unique populations. The variation found within the genotypic and morpho-physiological traits of P.decipiens appears to have a climatic determinant, but this is not always reflected by the algal partner. Although photobiont switching occurs on an evolutionary scale, there is little evidence to suggest an active environmentally induced response. These results suggest that this species, and therefore, other lichen species, and BSC ecosystems themselves may be significantly vulnerable to climate change and habitat loss.

  • 1589.
    Williams, Tom A.
    et al.
    Univ Bristol, Sch Earth Sci, Bristol BS8 1TQ, Avon, England.;Newcastle Univ, Inst Cell & Mol Biosci, Newcastle Upon Tyne NE2 4HH, Tyne & Wear, England..
    Szollosi, Gergely J.
    MTA ELTE Lendulet Evolutionary Genom Res Grp, H-1117 Budapest, Hungary..
    Spang, Anja
    Uppsala universitet, Science for Life Laboratory, SciLifeLab. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för cell- och molekylärbiologi, Molekylär evolution.
    Foster, Peter G.
    Nat Hist Museum, Dept Life Sci, London SW7 5BD, England..
    Heaps, Sarah E.
    Newcastle Univ, Inst Cell & Mol Biosci, Newcastle Upon Tyne NE2 4HH, Tyne & Wear, England.;Newcastle Univ, Sch Math & Stat, Newcastle Upon Tyne NE1 7RU, Tyne & Wear, England..
    Boussau, Bastien
    Univ Lyon 1, CNRS, Lab Biometrie & Biol Evolut, UMR5558, F-69622 Villeurbanne, France..
    Ettema, Thijs J. G.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för cell- och molekylärbiologi, Molekylär evolution. Uppsala universitet, Science for Life Laboratory, SciLifeLab.
    Embley, T. Martin
    Newcastle Univ, Inst Cell & Mol Biosci, Newcastle Upon Tyne NE2 4HH, Tyne & Wear, England..
    Integrative modeling of gene and genome evolution roots the archaeal tree of life2017Inngår i: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 114, nr 23, s. E4602-E4611Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A root for the archaeal tree is essential for reconstructing the metabolism and ecology of early cells and for testing hypotheses that propose that the eukaryotic nuclear lineage originated from within the Archaea; however, published studies based on outgroup rooting disagree regarding the position of the archaeal root. Here we constructed a consensus unrooted archaeal topology using protein concatenation and a multigene supertree method based on 3,242 single gene trees, and then rooted this tree using a recently developed model of genome evolution. This model uses evidence from gene duplications, horizontal transfers, and gene losses contained in 31,236 archaeal gene families to identify the most likely root for the tree. Our analyses support the monophyly of DPANN (Diapherotrites, Parvarchaeota, Aenigmarchaeota, Nanoarchaeota, Nanohaloarchaea), a recently discovered cosmopolitan and genetically diverse lineage, and, in contrast to previous work, place the tree root between DPANN and all other Archaea. The sister group to DPANN comprises the Euryarchaeota and the TACK Archaea, including Lokiarchaeum, which our analyses suggest are monophyletic sister lineages. Metabolic reconstructions on the rooted tree suggest that early Archaea were anaerobes that may have had the ability to reduce CO2 to acetate via the Wood-Ljungdahl pathway. In contrast to proposals suggesting that genome reduction has been the predominant mode of archaeal evolution, our analyses infer a relatively small-genomed archaeal ancestor that subsequently increased in complexity via gene duplication and horizontal gene transfer.

  • 1590. Wingler, Astrid
    et al.
    Stångberg, Emma Josefine
    Saxena, Triambak
    Mistry, Rupal
    Interactions between temperature and sugars in the regulation of leaf senescence in the perennial herb Arabis alpina L.2012Inngår i: Journal of integrative plant biology, ISSN 1744-7909, Vol. 54, nr 8, s. 595-605Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Annual plants usually flower and set seed once before senescence results in the death of the whole plant (monocarpic senescence). Leaf senescence also occurs in polycarpic perennials; even in "evergreen" species individual leaves senesce. In the annual model Arabidopsis thaliana sugars accumulate in the senescent leaves and senescence is accelerated by high sugar availability. Similar to A. thaliana, sugar contents increased with leaf age in the perennial Arabis alpina grown under warm conditions (22 °C day/18 night). At 5 °C, sugar contents in non-senescent leaves were higher than at a warm temperature, but dependent on the accession, either sugars did not accumulate or their contents decreased in old leaves. In A. alpina plants grown in their natural habitat in the Alps, sugar contents declined with leaf age. Growth at a cold temperature slightly delayed senescence in A. alpina. In both warm and cold conditions, an external glucose supply accelerated senescence, but natural variation was found in this response. In conclusion, sugar accumulation under warm conditions could accelerate leaf senescence in A. alpina plants, but genotype-specific responses and interactions with growth temperature are likely to influence senescence under natural conditions.

  • 1591. Winternitz, J. C.
    et al.
    Promerova, M.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Polakova, R.
    Vinker, M.
    Schnitzer, J.
    Munclinger, P.
    Babik, W.
    Radwan, J.
    Bryja, J.
    Albrecht, T.
    Effects of heterozygosity and MHC diversity on patterns of extra-pair paternity in the socially monogamous scarlet rosefinch2015Inngår i: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 69, nr 3, s. 459-469Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Extra-pair copulation without apparent direct benefits is an evolutionary puzzle that requires indirect fitness benefits to females to explain its ubiquity in socially monogamous mating systems. Using wild scarlet rosefinches (Carpodacus erythrinus), we tested if genetic benefits in the form of global (microsatellite) heterozygote advantage, adaptive genes (major histocompatibility complex), or complementary genes (using both markers) were responsible for female extra-pair mate choice, while considering that the benefits of mate choice may be conditional on female genotype. We found no evidence for assortative or relatedness-based mating (complementary genes), but higher MHC diversity, microsatellite heterozygosity, and condition were significantly related to male extra-pair paternity (EPP) success. In contrast, female probability of having extra-pair offspring decreased with increasing heterozygosity. Interestingly, extra-pair and within-pair males had higher heterozygosity than their female mates and extra-pair males had higher MHC supertype diversity. The only genetic difference between extra-pair and within-pair offspring was lower variance in MHC allelic diversity within extra-pair offspring, providing limited support for indirect genetic fitness benefits for the markers tested. Offspring had both higher neutral heterozygosity and number of MHC supertypes than adults, as well as significant identity disequilibrium, potentially suggesting that mates are chosen to increase offspring diversity in the period of the present study. Overall, our results point to an EPP heterozygote advantage for males, especially when involving less heterozygous females, and suggest that heterozygosity effects on reproduction may differ between the sexes.

  • 1592.
    Witman, Nevin
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för molekylär biovetenskap, Wenner-Grens institut.
    Heigwer, Jana
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för molekylär biovetenskap, Wenner-Grens institut.
    Thaler, Barbara
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för molekylär biovetenskap, Wenner-Grens institut.
    Lui, Weng-Onn
    Karolinska Inst, Karolinska Univ Hosp, Dept Oncol Pathol, Stockholm, Sweden.
    Morrison, Jamie Ian
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för molekylär biovetenskap, Wenner-Grens institut.
    miR-128 regulates non-myocyte hyperplasia, deposition of extracellular matrix and Islet1 expression during newt cardiac regeneration2013Inngår i: Developmental Biology, ISSN 0012-1606, E-ISSN 1095-564X, Vol. 383, nr 2, s. 253-263Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cardiovascular disease is a global scourge to society, with novel therapeutic approaches required in order to alleviate the suffering caused by sustained cardiac damage. MicroRNAs (miRNAs) are being touted as one such approach in the fight against heart disease, acting as possible post-transcriptional molecular triggers responsible for invoking cardiac regeneration. To further ones understanding of miRNAs and cardiac regeneration, it is prudent to learn from organisms that can intrinsically regenerate their hearts following injury. Using the red-spotted newt, an adult chordate capable of cardiac regeneration, we decided to delve deeper into the role miRNAs play during this process. RNA isolated from regenerating newt heart samples, was used in a microarray screen, to identify significantly expressed candidate miRNAs during newt cardiac regeneration. We performed quantitative qPCR analysis on several conserved miRNAs and found one in particular, miR-128, to be significantly elevated when cardiac hyperplasia is at its peak following injury. In-situ hybridisation techniques revealed a localised expression pattern for miR-128 in the cardiomyocytes and non-cardiomyocytes in close proximity to the regeneration zone and in vivo knockdown studies revealed a regulatory role for miR-128 in proliferating non-cardiomyocyte populations and extracellular matrix deposition. Finally, 3'UTR reporter assays revealed Islet1 as a biological target for miR-128, which was confirmed further through in vivo Islet1 transcriptional and translational expression analysis in regenerating newt hearts. From these studies we conclude that miR-128 regulates both cardiac hyperplasia and Islet1 expression during newt heart regeneration and that this information could be translated into future mammalian cardiac studies.

  • 1593. Witsenburg, F.
    et al.
    Clement, L.
    Lopez-Baucells, A.
    Palmeirim, J.
    Pavlinic, I.
    Scaravelli, D.
    Sevcik, M.
    Dutoit, Ludovic
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Salamin, N.
    Goudet, J.
    Christe, P.
    How a haemosporidian parasite of bats gets around: the genetic structure of a parasite, vector and host compared2015Inngår i: Molecular Ecology, ISSN 0962-1083, E-ISSN 1365-294X, Vol. 24, nr 4, s. 926-940Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Parasite population structure is often thought to be largely shaped by that of its host. In the case of a parasite with a complex life cycle, two host species, each with their own patterns of demography and migration, spread the parasite. However, the population structure of the parasite is predicted to resemble only that of the most vagile host species. In this study, we tested this prediction in the context of a vector-transmitted parasite. We sampled the haemosporidian parasite Polychromophilus melanipherus across its European range, together with its bat fly vector Nycteribia schmidlii and its host, the bent-winged bat Miniopterus schreibersii. Based on microsatellite analyses, the wingless vector, and not the bat host, was identified as the least structured population and should therefore be considered the most vagile host. Genetic distance matrices were compared for all three species based on a mitochondrial DNA fragment. Both host and vector populations followed an isolation-by-distance pattern across the Mediterranean, but not the parasite. Mantel tests found no correlation between the parasite and either the host or vector populations. We therefore found no support for our hypothesis; the parasite population structure matched neither vector nor host. Instead, we propose a model where the parasite's gene flow is represented by the added effects of host and vector dispersal patterns.

  • 1594.
    Wojczulanis-Jakubas, Katarzyna
    et al.
    Univ Gdansk, Dept Vertebrate Ecol & Zool, Fac Biol, Wita Stwosza 59, PL-80308 Gdansk, Poland..
    Drobniak, Szymon M.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi. Jagiellonian Univ, Inst Environm Sci, Gronostajowa 7, PL-30387 Krakow, Poland.
    Jakubas, Dariusz
    Univ Gdansk, Dept Vertebrate Ecol & Zool, Fac Biol, Wita Stwosza 59, PL-80308 Gdansk, Poland..
    Kulpinska-Chamera, Monika
    Univ Gdansk, Dept Vertebrate Ecol & Zool, Fac Biol, Wita Stwosza 59, PL-80308 Gdansk, Poland..
    Chastel, Olivier
    CNRS, CEBC, UMR 7372, F-79360 Villiers En Bois, France.;Univ Rochelle, F-79360 Villiers En Bois, France..
    Assortative mating patterns of multiple phenotypic traits in a long-lived seabird2018Inngår i: Ibis, ISSN 0019-1019, E-ISSN 1474-919X, Vol. 160, nr 2, s. 464-469Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Choosing the right mate is crucial for successful breeding, particularly in monogamous species with long and extensive bi-parental care, and when the breeding pair is presumed to last many seasons. We investigated the degree of assortative mating in the Little Auk Alle alle, a long-lived seabird with long-term pair bonds and bi-parental care for fixed (morphological) and labile (physiological, behavioural) traits. Using randomization tests, we suggest assortative mating with respect to wing length, extent of the white area on the upper eyelid and hormonal stress response (the difference between stress-induced and baseline corticosterone levels). We discuss how the assortative mating patterns that we found in the Little Auk may be adaptive.

  • 1595.
    Wolf, Jochen B. W.
    et al.
    Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Biology, August-Thienemannstr. 2, 24306 Plön, Germany.
    Bayer, Till
    Haubold, Bernhard
    Schilhabel, Markus
    Rosenstiel, Philip
    Tautz, Diethard
    Nucleotide divergence versus gene expression differentiation: comparative transcriptome sequencing in natural isolates from the carrion crow and its hybrid zone with the hooded crow2010Inngår i: Molecular Ecology, ISSN 0962-1083, E-ISSN 1365-294X, Vol. 19, nr Suppl. 1, s. 162-175Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Recent advances in sequencing technology promise to provide new strategies for studying population differentiation and speciation phenomena in their earliest phases. We focus here on the black carrion crow (Corvus [corone] corone), which forms a zone of hybridization and overlap with the grey coated hooded crow (Corvus [corone] cornix). However, although these semispecies are taxonomically distinct, previous analyses based on several types of genetic markers did not reveal significant molecular differentiation between them. We here corroborate this result with sequence data obtained from a set of 25 nuclear intronic loci. Thus, the system represents a case of a very early phase of species divergence that requires new molecular approaches for its description. We have therefore generated RNAseq expression profiles using barcoded massively parallel pyrosequencing of brain mRNA from six individuals of the carrion crow and five individuals from a hybrid zone with the hooded crow. We obtained 856 675 reads from two runs, with average read length of 270 nt and coverage of 8.44. Reads were assembled de novo into 19 552 contigs, 70% of which could be assigned to annotated genes in chicken and zebra finch. This resulted in a total of 7637 orthologous genes and a core set of 1301 genes that could be compared across all individuals. We find a clear clustering of expression profiles for the pure carrion crow animals and disperse profiles for the animals from the hybrid zone. These results suggest that gene expression differences may indeed be a sensitive indicator of initial species divergence.

  • 1596. Wong, B. B. M.
    et al.
    Svensson, P. Andreas
    School of Biological Sciences, Monash University, Melbourne, VIC, 3800, Australia.
    Strategic male signalling effort in a desert-dwelling fish2009Inngår i: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 63, nr 4, s. 543-549Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Males often use elaborate courtship displays to attract females for mating. Much attention, in this regard, has been focused on trying to understand the causes and consequences of signal variation among males. Far less, by contrast, is known about within-individual variation in signal expression and, in particular, the extent to which males may be able to strategically adjust their signalling output to try to maximise their reproductive returns. Here, we experimentally investigated male courtship effort in a fish, the Australian desert goby, Chlamydogobius eremius. When offered a simultaneous choice between a large and a small female, male gobies spent significantly more time associating with, and courting, the former, probably because larger females are also more fecund. Male signalling patterns were also investigated under a sequential choice scenario, with females presented one at a time. When first offered a female, male courtship was not affected by female size. However, males adjusted their courtship effort towards a second female depending on the size of the female encountered previously. In particular, males that were first offered a large female significantly reduced their courtship effort when presented with a subsequent, smaller, female. Our findings suggest that males may be able to respond adaptively to differences in female quality, and strategically adjust their signalling effort accordingly.

  • 1597.
    Wärmländer, Sebastian K. T. S.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för biokemi och biofysik.
    Sholts, Sabrina B.
    Erlandson, Jon M.
    Gjerdrum, Thor
    Westerholm, Roger
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för analytisk kemi.
    Ancient bitumen use and polycyclic aromatic hydrocarbons exposure: a potential factor in the health decline of prehistoric California Indians.2011Inngår i: American Journal of Physical Anthropology: Supplement: Program of the 80th Annual Meeting of the American Association of Physical Anthropologists, 2011, Vol. 144, s. vol 144-suppl.52Konferansepaper (Annet vitenskapelig)
  • 1598.
    Xenikoudakis, Georgios
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen. Swedish Museum of National History, Sweden.
    Ersmark, Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen. Swedish Museum of National History, Sweden.
    Tison, J. -L.
    Waits, L.
    Kindberg, J.
    Swenson, J. E.
    Dalén, Love
    Swedish Museum of National History, Sweden.
    Consequences of a demographic bottleneck on geneticstructure and variation in the Scandinavian brown bear2015Inngår i: Molecular Ecology, ISSN 0962-1083, E-ISSN 1365-294X, Vol. 24, nr 13, s. 3441-3454Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Scandinavian brown bear went through a major decline in population size approximately 100years ago, due to intense hunting. After being protected, the population subsequently recovered and today numbers in the thousands. The genetic diversity in the contemporary population has been investigated in considerable detail, and it has been shown that the population consists of several subpopulations that display relatively high levels of genetic variation. However, previous studies have been unable to resolve the degree to which the demographic bottleneck impacted the contemporary genetic structure and diversity. In this study, we used mitochondrial and microsatellite DNA markers from pre- and postbottleneck Scandinavian brown bear samples to investigate the effect of the bottleneck. Simulation and multivariate analysis suggested the same genetic structure for the historical and modern samples, which are clustered into three subpopulations in southern, central and northern Scandinavia. However, the southern subpopulation appears to have gone through a marked change in allele frequencies. When comparing the mitochondrial DNA diversity in the whole population, we found a major decline in haplotype numbers across the bottleneck. However, the loss of autosomal genetic diversity was less pronounced, although a significant decline in allelic richness was observed in the southern subpopulation. Approximate Bayesian computations provided clear support for a decline in effective population size during the bottleneck, in both the southern and northern subpopulations. These results have implications for the future management of the Scandinavian brown bear because they indicate a recent loss in genetic diversity and also that the current genetic structure may have been caused by historical ecological processes rather than recent anthropogenic persecution.

  • 1599.
    Xiong, Ye
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för biologisk grundutbildning. Molecular Ecology and Evolution Lab , Lund University.
    Early dietary effects of arachidonic acid on gene expression linked to  immune response and metabolism in rural and urban Great Tit (Parus Major) nestlings2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This study was conducted to test the silver spoon hypothesis that earlylife nutritional conditions impact development, performance and fitness of the birdsgreat tit (Parus major) nestlings. We investigated whether fatty acid affects immunityand metabolism during the altricial period by examining the expressions of geneTLR4 (immunity related) and COX 2 (metabolism related) against a dietarymanipulation on great tit nestlings in urban vs. rural environments. The resultssuggested that arachidonic acid had no significant effect on TLR4 expression, but atendency to induce immune response, regardless of urban or rural conditions. Thestrength of immune response was however negatively correlated with laying date. Theurban great tit nestlings had a higher COX 2 gene expression than rural ones, andarachidonic acid suppressed COX 2.Thus no strong support to the hypothesis was found for the studied great titpopulations. It showed, however, i) there is a tendency of increasing immune responsewith extra fatty acid in the diet, and ii) arachidonic acid suppress metabolism. Fattyacid involved in a multiple physiological processes and this complex need to beelaborated in future studies.

  • 1600.
    Xu, Bo
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för neurovetenskap.
    Evolutionary and Pharmacological Studies of NPY and QRFP Receptors2014Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The neuropeptide Y (NPY) system consists of 3-4 peptides and 4-7 receptors in vertebrates. It has powerful effects on appetite regulation and is involved in many other biological processes including blood pressure regulation, bone formation and anxiety. This thesis describes studies of the evolution of the NPY system by comparison of several vertebrate species and structural studies of the human Y2 receptor, which reduces appetite, to identify amino acid residues involved in peptide-receptor interactions.

    The NPY system was studied in zebrafish (Danio rerio), western clawed frog (Xenopus tropicalis), and sea lamprey (Petromyzon marinus). The receptors were cloned and functionally expressed and their pharmacological profiles were determined using the native peptides in either binding studies or a signal transduction assay. Some peptide-receptor preferences were observed, indicating functional specialization.

    A receptor family closely related to the NPY receptors, called the QRFP receptors, was investigated. A QRFP receptor was cloned from amphioxus, Branchistoma floridae, showing that the receptor arose before the origin of the vertebrates. Evolutionary studies demonstrated that the ancestral vertebrate had as many as four QRFP receptors, only one of which remains in mammals today. This correlates with the NPY receptor family, located in the same chromosomal regions, which had seven members in the ancestral vertebrate but only 4-5 in living mammals. Some vertebrates have considerably more complex NPY and QRFP receptor systems than humans and other mammals.

    Two studies investigated interactions of NPY-family peptides with the human Y2 receptor. Candidate residues, selected based on structural modeling and docking, were mutated to disrupt possible interactions with peptide ligands. The modified receptors were expressed in cultured cells and investigated by measuring binding and functional responses. Several receptor residues were found to influence peptide-receptor interactions, some of which are involved in maintaining receptor structure. In a pilot study, the kinetics of peptide-receptor interaction were found to be very slow, of the order several hours.

    In conclusion, this thesis clarifies evolutionary relationships for the complex NPY and QRFP peptide-receptor systems and improves the structural models of the human NPY-family receptors, especially Y2. These results will hopefully facilitate drug design for targeting of NPY-family receptors.

293031323334 1551 - 1600 of 1655
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