Patterns Of Genetic Differentiation Research Articles

Population genetics of caribou in the Alaska-Yukon border region: implications for designation of conservation units and small herd persistence

AbstractBetter knowledge of genetic relationships between the Fortymile caribou herd and its neighbors is needed for conservation decision-making in Canada. Here, we contribute the first fine-scale analysis of genetic population structure in nine contiguous caribou herds at the geographic boundaries between Barren-ground and Northern Mountain caribou, and at the Alaska-Yukon border. Using pairwise differentiation metrics, STRUCTURE, and discriminant analysis of principal components (DAPC) to analyze 15 microsatellite loci in 379 caribou, we found complex patterns of genetic differentiation. The Fortymile was the only herd assigned to more than one genetic cluster, indicative of its history as a larger herd whose range expansions and gene flow to other herds were likely important to maintaining diversity across a functioning genetic metapopulation. Some small herds (Chisana, Klaza, and White Mountains) were genetically distinct, while others (Hart River, Clear Creek, Mentasta) exhibited little differentiation from herds they occasionally overlap, including herds assigned to different conservation units (DUs). This genetic connectivity does not result from demographic connectivity, as episodic contact during rut, rather than herd switching, is the likely mechanism. Unusually, one small herd (White Mountains) maintained genetic differentiation despite rut overlap with Fortymile. Our data reveal that some herds with different ecological and behavioral attributes are demographically independent but nonetheless genetically connected. Thus, we suggest that managing caribou for an appropriate level of genetic connectivity, while also supporting herd persistence, will be essential to conserve caribou genetic diversity in the region.

Copy number variation and elevated genetic diversity at immune trait loci in Atlantic and Pacific herring

BackgroundGenome-wide comparisons of populations are widely used to explore the patterns of nucleotide diversity and sequence divergence to provide knowledge on how natural selection and genetic drift affect the genome. In this study we have compared whole-genome sequencing data from Atlantic and Pacific herring, two sister species that diverged about 2 million years ago, to explore the pattern of genetic differentiation between the two species.ResultsThe genome comparison of the two species revealed high genome-wide differentiation but with islands of remarkably low genetic differentiation, as measured by an FST analysis. However, the low FST observed in these islands is not caused by low interspecies sequence divergence (dxy) but rather by exceptionally high estimated intraspecies nucleotide diversity (π). These regions of low differentiation and elevated nucleotide diversity, termed high-diversity regions in this study, are not enriched for repeats but are highly enriched for immune-related genes. This enrichment includes genes from both the adaptive immune system, such as immunoglobulin, T-cell receptor and major histocompatibility complex genes, as well as a substantial number of genes with a role in the innate immune system, e.g. novel immune-type receptor, tripartite motif and tumor necrosis factor receptor genes. Analysis of long-read based assemblies from two Atlantic herring individuals revealed extensive copy number variation in these genomic regions, indicating that the elevated intraspecies nucleotide diversities were partially due to the cross-mapping of short reads.ConclusionsThis study demonstrates that copy number variation is a characteristic feature of immune trait loci in herring. Another important implication is that these loci are blind spots in classical genome-wide screens for genetic differentiation using short-read data, not only in herring, likely also in other species harboring qualitatively similar variation at immune trait loci. These loci stood out in this study because of the relatively high genome-wide baseline for FST values between Atlantic and Pacific herring.

Historical biogeography of the Saharan horned viper enlightens past dynamics of hyperarid desert habitats

Hyperarid habitats comprise the most dominant and harsh portion of the Sahara Desert, yet how local biotas have responded to paleoclimatic shifts and landscape heterogeneity remains unclear. Here, we assess the historical biogeography of Cerastes cerastes, a conspicuous but poorly known vertebrate inhabiting the hyperarid Sahara, to understand the links between intermittent and stable climatic suitability and patterns of genetic diversity and differentiation in these extreme environments. We combine phylogeographic and ecological modelling tools using a comprehensive species dataset, which includes DNA samples (n = 62) and occurrence records (n = 557) covering most of its range. We show that paleoclimatic oscillations were major evolutionary and biogeographic drivers in C. cerastes, which exhibits different levels of intra-specific diversity and allopatric lineage structuration across the desert. High lineage richness in the north-western Sahara contrasts with an overall lack of genetic diversity throughout the central and eastern Sahara. Climatic refugia along the desert's periphery and around mountain patches harbour single endemic lineages, stressing the links between stable climatic conditions and population isolation and divergence. Increasing climatic suitability during historical arid phases prompted widespread connectivity across the desert. This study lays the groundwork for better understanding the historical dynamics of the hyperarid Sahara.

Mitogenomic Characterization of South African Leopards and the Effect of Past Climatic Events

Revealing phylogeographic structure is important for accurate subspecies delineation and understanding a species’ evolutionary history. In leopards (Panthera pardus), there are currently nine subspecies recognized. On the African continent, only one subspecies occurs (P. p. pardus), although mitochondrial DNA from historical samples suggests the presence of three putative continental clades: (1) West Africa (WA), (2) Central Africa (CA), and (3) Southern Africa (SA). So far, whole genome data did not recover this phylogeographic structure, although leopards in the southern periphery of their distribution range in Africa have not yet been investigated in detail. The Mpumalanga province of South Africa is of particular interest, as here, the CA and the SA clade possibly meet. The aim of this study was to characterize the first mitogenomes of African leopards from Mpumalanga, to help clarifying how South African leopards fit into continental patterns of genetic differentiation. Complete mitogenomes from nine leopards, including a strawberry leopard, were assembled de novo and included in phylogenetic analysis, in combination with 32 publicly available mitogenomes. Bayesian inference and maximum likelihood analyses identified two deeply diverged putative clades within South Africa, which were more genetically distinct than two subspecies in Asia. The clades dated back to 0.76-0.86 million years ago, indicating that they originated during the climatically unstable Mid-Pleistocene, as seen in other large mammals. The Pleistocene refuge theory states that the maintenance of savanna refugia in East and Southern Africa promoted the divergence between populations. As such, leopards may reflect the unique climatic history of southern Africa, which has resulted in eminent and endemic genetic diversity.

The role of neutral and adaptive evolutionary processes on patterns of genetic diversity across small cave-dwelling populations of Icelandic Arctic charr (Salvelinus alpinus).

Understanding the adaptability of small populations in the face of environmental change is a central problem in evolutionary biology. Solving this problem is challenging because neutral evolutionary processes that operate on historical and contemporary timescales can override the effects of selection in small populations. We assessed the effects of isolation by colonization (IBC), isolation by dispersal limitation (IBDL) as reflected by a pattern of isolation by distance (IBD), and isolation by adaptation (IBA) and the roles of genetic drift and gene flow on patterns of genetic differentiation among 19 cave-dwelling populations of Icelandic Arctic charr (Salvelinus alpinus). We detected evidence of IBC based on the genetic affinity of nearby cave populations and the genetic relationships between the cave populations and the presumed ancestral population in the lake. A pattern of IBD was evident regardless of whether high-level genetic structuring (IBC) was taken into account. Genetic signatures of bottlenecks and lower genetic diversity in smaller populations indicate the effect of drift. Estimates of gene flow and fish movement suggest that gene flow is limited to nearby populations. In contrast, we found little evidence of IBA as patterns of local ecological and phenotypic variation showed little association with genetic differentiation among populations. Thus, patterns of genetic variation in these small populations likely reflect localized gene flow and genetic drift superimposed onto a larger-scale structure that is largely a result of colonization history. Our simultaneous assessment of the effects of neutral and adaptive processes in a tractable and replicated system has yielded novel insights into the evolution of small populations on both historical and contemporary timescales and over a smaller spatial scale than is typically studied.

Social and genetic connectivity despite ecological variation in a killer whale network.

Philopatric kin-based societies encourage a narrow breadth of conservative behaviours owing to individuals primarily learning from close kin, promoting behavioural homogeneity. However, weaker social ties beyond kin, and across a behaviourally diverse social landscape, could be sufficient to induce variation and a greater ecological niche breadth. We investigated a network of 457 photo-identified killer whales from Norway (548 encounters in 2008-2021) with diet data available (46 mixed-diet individuals feeding on both fish and mammals, and 411 exclusive fish-eaters) to quantify patterns of association within and between diet groups, and to identify underlying correlates. We genotyped a subset of 106 whales to assess patterns of genetic differentiation. Our results suggested kinship as main driver of social bonds within and among cohesive social units, while diet was most likely a consequence reflective of cultural diffusion, rather than a driver. Flexible associations within and between ecologically diverse social units led to a highly connected network, reducing social and genetic differentiation between diet groups. Our study points to a role of social connectivity, in combination with individual behavioural variation, in influencing population ecology in killer whales.

The weak genetic structure of Melolontha melolontha (L.) and Melolontha hippocastani (Fabr.), two important forest pests, indicates their large population sizes and effective gene flow

Abstract Cockchafers Melolontha spp. are polyphagous root pests and outbreak species of considerable economic importance to forestry in Europe. Knowledge of genetic diversity within and between cockchafer populations is largely unexplored but could lead to more effective monitoring and management strategies of these pests. In this study, we fill several gaps in the knowledge of the genetic population structure of Melolontha melolontha and Melolontha hippocastani. Using microsatellite loci and over 200 individuals per species, we examined the genetic structure of Melolontha spp. populations collected from three primary outbreak areas in central and southeastern Poland. We demonstrated that our focal species share some common genetic patterns, such as considerable genetic diversity within subpopulations (within sampling sites) with minor effects of past bottlenecks possibly masked by current population sizes. The estimates of effective population sizes, although subject to wide credibility intervals, indicated a large number of individuals contributing to further generations of the population. The migration rates exceed the threshold of one per generation required for gene flow and maintenance of population equilibrium, indicating limited impact from forest management practices on either cockchafer species. While genetic differentiation was observed in M. melolontha populations, supported by various indices (fixation index, principal coordinate analysis, assignment tests), the M. hippocastani populations were genetically similar. This disparity may hint at the potential historical divergence between these species. In this aspect, more detailed phylogeographic and population genetic studies covering a large area of the Palaearctic distributions of both species are required. Our findings constitute one of the initial efforts aimed at delineating the genetic diversity, differentiation, population structure, gene flow, and migration patterns within Melolontha spp. This exploration is especially significant for M. hippocastani, given its completely unexplored genetic population structure.

Genetic Diversity and Population Structure of Chinese Longsnout Catfish (Leiocassis longirostris) Using Microsatellite DNA Markers

The Chinese longsnout catfish (Leiocassis longirostris) is an economically important freshwater fish in China; however, its wild resources have declined dramatically in recent decades. Understanding the genetic structure of Chinese longsnout catfish populations is crucial to guide breeding programs and fishy restoration. In this study, 15 highly polymorphic microsatellite DNA loci were used to evaluate its genetic diversity and population structure. Chinese longsnout catfish populations show high genetic diversity; they do not show significant genetic differentiation or systematic geographic pattern of variation. From the upper to the lower reaches of the Yangtze River, the genetic diversity of Chinese longsnout catfish populations showed an increasing trend. The Gezhouba and Three Gorges dams, which physically divide the Yangtze River into upstream and mid-downstream sections, did not contribute to the genetic differentiation of Chinese longsnout catfish populations. Hence, the source of broodstock is not critical for within-river breeding programs and stock enhancement to restore the wild population. In addition, possible effects of dams on differentiation among populations are crucial and long-term evaluation is essential.

Conservation Genetics of the Endangered Lompoc Yerba Santa (Eriodictyon capitatum Eastw., Namaceae), including Phylogenomic Insights into the Evolution of Eriodictyon.

Eriodictyon capitatum (Namaceae) is a narrowly distributed shrub endemic to western Santa Barbara County, where it is known from only 10 extant California Natural Diversity Database element occurrences (EOs). Owing to low numbers of plants in nature, a limited overall extent, and multiple current threats, E. capitatum is listed as Endangered under the Federal Endangered Species Act and as Rare under the California Native Plant Protection Act. In the present study, high-throughput DNA sequence data were analyzed to investigate genetic diversity within and among all accessible EOs; to determine the extent of genetic isolation among EOs; to examine clonality within EOs; and to examine the taxonomic circumscriptions of E. capitatum, E. altissimum, E. angustifolium, and E. californicum through phylogenomic analysis. Population genetic analyses of E. capitatum reveal a pattern of strong genetic differentiation by location/EO. The clonality assessment shows that certain small EOs may support relatively few multilocus genotypes. The phylogenomic analyses strongly support the present-day taxonomic circumscriptions of both E. altissimum and E. capitatum, showing them to be reciprocally monophyletic and sister with strong support. Taken together, these results paint a picture of an evolutionarily and morphologically distinct species known from relatively few, genetically isolated stations.

Apomixis goes a long way: Genetic evidence of persistence and long‐distance seed dispersal in an ancient landscape

AbstractAimApomixis is a widespread trait in extreme environments worldwide, yet phylogeographical studies for species exhibiting these complex reproductive systems are still limited to temperate zones in the Northern Hemisphere. Through analyses of a combination of adult plants and seedlings, and nuclear and chloroplast DNA, we assessed the contemporary genetic outcomes of apomixis and phylogeographical patterns in an arid unglaciated landscape to understand the evolutionary trajectory of apomictic species.LocationPilbara bioregion, north‐western Australia.TaxonSenna glutinosa subsp. glutinosa.Materials and MethodsSpatial patterns of genetic diversity and differentiation in three chloroplast regions and 17 nuclear microsatellite markers were evaluated in 480 plants from 20 populations of S. glutinosa subsp. glutinosa across the Pilbara bioregion. We also germinated and genotyped seed for a progeny analysis to quantify polyembryony and the relative frequency of asexual versus sexual reproduction.ResultsWe found frequent polyembryony and a high proportion of asexual offspring (84.56%), resulting in low within‐population genotypic diversity. The nuclear dataset identified 72 multilocus lineages (MLLs) with moderate pairwise population genetic fixation and low differentiation among populations with no geographically structured genetic clustering. Chloroplast DNA showed high haplotype diversity and a widespread distribution of haplotypes. Only one peripheral population presented a single unique haplotype and MLL.Main ConclusionsAnalysis of this woody perennial in an arid landscape shows the influence of apomixis on genetic patterns and species persistence. Haplotype diversity was indicative of long‐term persistence within the ancient Pilbara region. Widespread distribution of haplotypes and sharing of several nuclear MLLs among distant populations indicated extensive seed dispersal throughout the study area. The combination of polyploidy, facultative apomixis and extensive seed dispersal maintains genetic variability within local populations and promotes the spread of advantageous genotypes across wide geographical distances. Therefore, apomixis, rather than an evolutionary ‘dead‐end’, can be regarded as a mechanism facilitating evolutionary success of apomictic species in extreme and complex environments.

Genetic diversity and genetic differentiation pattern of Tuta absoluta across China

Genetic diversity and genetic differentiation pattern of Tuta absoluta across China

Changes in the spatio-temporal genetic structure of Baltic sea trout (Salmo trutta L.) over two decades: direct and indirect effects of stocking

Several countries have implemented stocking programmes to enhance abundance and fish production by releases of hatchery-reared fish. However, due to fluctuations in population size, stocking history, and potential indirect effects of straying of hatchery-reared fish, it is often difficult to predict how these factors will affect genetic diversity and differentiation patterns among wild populations. This study characterized the population genetic structure and temporal variability of four Estonian sea trout populations by evaluating the degrees of direct and indirect genetic impacts of stocking over two decades using 14 microsatellite loci. Our results demonstrate considerable temporal change combined with weak genetic structuring among studied sea trout populations. We found a reduction of the overall level of genetic differentiation combined with the tendency for increased genetic diversity, and an effective number of breeders (Nb) over the study period. Furthermore, we found that immigration rates (m) from hatchery stocks were highest in the population subjected to direct stocking and in non-stocked populations that were located geographically closer to the stocked rivers. This work suggests that hatchery releases have influenced the genetic diversity and structuring of studied sea trout populations. However, the impact of hatchery releases on the adaptive variation and fitness-related traits in wild trout populations remains to be revealed by more informative genetic markers. This study illustrates the dynamic nature of the population genetic structure of sea trout and the value of long-term genetic monitoring for management and conservation.

Mitonuclear Sex Determination? Empirical Evidence from Bivalves.

Genetic elements encoded in nuclear DNA determine the sex of an individual in many animals. In certain bivalve lineages that possess doubly uniparental inheritance (DUI), mitochondrial DNA (mtDNA) has been hypothesized to contribute to sex determination. In these cases, females transmit a female mtDNA to all offspring, while male mtDNA (M mtDNA) is transmitted only from fathers to sons. Because M mtDNA is inherited in the same way as Y chromosomes, it has been hypothesized that mtDNA may be responsible for sex determination. However, the role of mitochondrial and nuclear genes in sex determination has yet to be validated in DUI bivalves. In this study, we used DNA, RNA, and mitochondrial short noncoding RNA (sncRNA) sequencing to explore the role of mitochondrial and nuclear elements in the sexual development pathway of the freshwater mussel Potamilus streckersoni (Bivalvia: Unionida). We found that the M mtDNA sheds a sncRNA partially within a male-specific mitochondrial gene that targets a pathway hypothesized to be involved in female development and mitophagy. RNA-seq confirmed the gene target was significantly upregulated in females, supporting a direct role of mitochondrial sncRNAs in gene silencing. These findings support the hypothesis that M mtDNA inhibits female development. Genome-wide patterns of genetic differentiation and heterozygosity did not support a nuclear sex-determining region, although we cannot reject that nuclear factors are involved with sex determination. Our results provide further evidence that mitochondrial loci contribute to diverse, nonrespiratory functions and additional insights into an unorthodox sex-determining system.

Genetic diversity of a short-ranged endemic terrestrial snail.

The factors that influence population structure and connectivity are unknown for most terrestrial invertebrates but are of particular interest both for understanding the impacts of disturbance and for determining accurate levels of biodiversity and local endemism. The main objective of this study was to determine the historical patterns of genetic differentiation and contemporary gene flow in the terrestrial snail, Austrochloritis kosciuszkoensis (Shea & O. L. Griffiths, 2010). Snails were collected in the Mt Buffalo and Alpine National Parks in Victoria, in a bid to understand how populations of this species are connected both within continuous habitat and between adjacent, yet separate environments. Utilising both mitochondrial DNA (mtDNA) and single nucleotide polymorphism (SNP) data, the degree of population structure was determined within and between sites. Very high levels of genetic divergence were found between the Mt Buffalo and Alpine snails, with no evidence for genetic exchange detected between the two regions, indicating speciation has possibly occurred between the two regions. Our analyses of the combined mtDNA and nDNA (generated from SNPs) data have revealed patterns of genetic diversity that are consistent with a history of long-term isolation and limited connectivity. This history may be related to past cycles of changes to the climate over hundreds of thousands of years, which have, in part, caused the fragmentation of Australian forests. Within both regions, extremely limited gene flow between separate populations suggests that these land snails have very limited dispersal capabilities across existing landscape barriers, especially at Mt Buffalo: here, populations only 5 km apart from each other are genetically differentiated. The distinct genetic divergences and clearly reduced dispersal ability detected in this data explain the likely existence of at least two previously unnamed cryptic Austrochloritis species within a 30-50 km radius, and highlight the need for more concentrated efforts to understand population structure and gene flow in terrestrial invertebrates.

Comparative phylogeography reveals dissimilar genetic differentiation patterns in two sympatric amphibian species.

Global climate change is expected to have a profound effect on species distribution. Due to the temperature constraints, some narrow niche species could shift their narrow range to higher altitudes or latitudes. In this study, we explored the correlation between species traits, genetic structure, and geographical range size. More specifically, we analyzed how these variables are affected by differences in fundamental niche breadth or dispersal ability in the members of two sympatrically distributed stream-dwelling amphibian species (frog, Quasipaa yei; salamander, Pachyhynobius shangchengensis), in Dabie Mountains, East China. Both species showed relatively high genetic diversity in most geographical populations and similar genetic diversity patterns (JTX, low; BYM, high) correlation with habitat changes and population demography. Multiple clustering analyses were used to disclose differentiation among the geographical populations of these two amphibian species. Q. yei disclosed the relatively shallow genetic differentiation, while P. shangchengensis showed an opposite pattern. Under different historical climatic conditions, all ecological niche modeling disclosed a larger suitable habitat area for Q. yei than for P. shangchengensis; these results indicated a wider environment tolerance or wider niche width of Q. yei than P. shangchengensis. Our findings suggest that the synergistic effects of environmental niche variation and dispersal ability may help shape genetic structure across geographical topology, particularly for species with extremely narrow distribution.

The use of pinned specimens helps uncover patterns of genetic differentiation and signatures of selection in a wild pollinator

The use of pinned specimens helps uncover patterns of genetic differentiation and signatures of selection in a wild pollinator

Balancing selection shapes population differentiation of major histocompatibility complex genes in wild golden snub-nosed monkeys

Abstract Small and isolated populations face several intrinsic risks, such as genetic drift, inbreeding depression, and reduced gene flow. Thus, patterns of genetic diversity and differentiation have become an important focus of conservation genetics research. The golden snub-nosed monkey Rhinopithecus roxellana, an endangered species endemic to China, has experienced rapid reduction in population size and severe population fragmentation over the past few decades. We measured the patterns of genetic diversity and population differentiation using both neutral microsatellites and adaptive major histocompatibility complex (MHC) genes in 2 R. roxellana populations (DPY and GNG) distributed on the northern and southern slopes of the Qinling Mountains, respectively. Eight MHC-linked haplotypes formed by 5 DQA1 alleles, 5 DQB1 alleles, 5 DRB1 alleles, and 4 DRB2 alleles were detected in the 2 populations. The larger GNG population showed higher genetic variation for both MHC and microsatellites than the smaller DPY population, suggesting an effect of genetic drift on genetic variation. Genetic differentiation index (FST) outlier analyses, principal coordinate analysis (PCoA), and inferred population genetic structure showed lower genetic differentiation in the MHC variations than microsatellites, suggesting that pathogen-mediated balancing selection, rather than local adaptation, homogenized the MHC genes of both populations. This study indicates that both balancing selection and genetic drift may shape genetic variation and differentiation in small and fragmented populations.

Effects of Climatic Change on Phylogeography and Ecological Niche of the Endemic Herb Elymus breviaristatus on the Qinghai-Tibet Plateau.

Past climatic and topographic variations have created strong biogeographic barriers for alpine species and are key drivers of the distribution of genetic variation and population dynamics of species on the Qinghai-Tibet Plateau (QTP). Therefore, to better conserve and use germplasm resources, it is crucial to understand the distribution and differentiation of genetic variation within species. Elymus breviaristatus, an ecologically important rare grass species with strong resistance, is restricted to a limited area of the QTP. In this study, we investigated the phylogeography of E. breviaristatus using five chloroplast genes and spacer regions in natural populations distributed along the eastern QTP. We identified a total of 25 haplotypes among 216 individuals from 18 E. breviaristatus populations, which were further classified into four haplogroups based on geographical distribution and haplotype network analysis. Notably, we did not observe any signs of population expansion. High genetic diversity was exhibited at both species and population levels, with precipitation being the main limiting factor for population genetic diversity levels. Higher genetic diversity was exhibited by populations located near the Mekong-Salween Divide genetic barrier, suggesting that they may have served as a glacial refuge. The significant pattern of genetic differentiation by environmental isolation highlights the influence of heterogeneous environments on the genetic structure of E. breviaristatus populations. Additionally, the results of ecological niche models indicated that the geographic distribution of E. breviaristatus populations has decreased rapidly since the Last Glacial Maximum but is not threatened by future global warming.

Patterns of genetic differentiation imply distinct phylogeographic history of the mosquito species Anopheles messeae and Anopheles daciae in Eurasia.

Detailed knowledge of phylogeography is important for control of mosquito species involved in the transmission of human infectious diseases. Anopheles messeae is a geographically widespread and genetically diverse dominant vector of malaria in Eurasia. A closely related species, An. daciae, was originally distinguished from An. messeae based on five nucleotide substitutions in its ribosomal DNA (rDNA). However, the patterns of phylogeographic history of these species in Eurasia remain poorly understood. Here, using internal transcribed spacer 2 (ITS2) of rDNA and karyotyping for the species identification we determined the composition of five Anopheles species in 28 locations in Eurasia. Based on the frequencies of 11 polymorphic chromosomal inversions used as genetic markers, a large-scale population genetics analysis was performed of 1932 mosquitoes identified as An. messeae, An. daciae and their hybrids. The largest genetic differences between the species were detected in the X sex chromosome suggesting a potential involvement of this chromosome in speciation. The frequencies of autosomal inversions in the same locations differed by 13%-45% between the species demonstrating a restricted gene flow between the species. Overall, An. messeae was identified as a diverse species with a more complex population structure than An. daciae. The clinal gradients in frequencies of chromosomal inversions were determined in both species implicating their possible involvement in climate adaptations. The frequencies of hybrids were low ~1% in northern Europe but high up to 50% in south-eastern populations. Thus, our study revealed critical differences in patterns of phylogeographic history between An. messeae and An. daciae in Eurasia. This knowledge will help to predict the potential of the malaria transmission in the northern territories of the continent.

Epigenomic divergence correlates with sequence polymorphism in Arabidopsis paralogs.

Processes affecting rates of sequence polymorphism are fundamental to the evolution of gene duplicates. The relationship between gene activity and sequence polymorphism can influence the likelihood that functionally redundant gene copies are co-maintained in stable evolutionary equilibria vs other outcomes such as neofunctionalization. Here, we investigate genic variation in epigenome-associated polymorphism rates in Arabidopsis thaliana and consider whether these affect the evolution of gene duplicates. We compared the frequency of sequence polymorphism and patterns of genetic differentiation between genes classified by exon methylation patterns: unmethylated (unM), gene-body methylated (gbM), and transposon-like methylated (teM) states, which reflect divergence in gene expression. We found that the frequency of polymorphism was higher in teM (transcriptionally repressed, tissue-specific) genes and lower in gbM (active, constitutively expressed) genes. Comparisons of gene duplicates were largely consistent with genome-wide patterns - gene copies that exhibit teM accumulate more variation, evolve faster, and are in chromatin states associated with reduced DNA repair. This relationship between expression, the epigenome, and polymorphism may lead to the breakdown of equilibrium states that would otherwise maintain genetic redundancies. Epigenome-mediated polymorphism rate variation may facilitate the evolution of novel gene functions in duplicate paralogs maintained over evolutionary time.