| 1. |
- Ferreira, Mafalda S, et al.
(författare)
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The Legacy of Recurrent Introgression during the Radiation of Hares
- 2020
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Ingår i: Systematic Biology. - : Oxford University Press (OUP). - 1063-5157 .- 1076-836X. ; 70:3, s. 593-607
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Tidskriftsartikel (refereegranskat)abstract
- Hybridization may often be an important source of adaptive variation, but the extent and long-term impacts of introgression have seldom been evaluated in the phylogenetic context of a radiation. Hares (Lepus) represent a widespread mammalian radiation of 32 extant species characterized by striking ecological adaptations and recurrent admixture. To understand the relevance of introgressive hybridization during the diversification of Lepus, we analyzed whole exome sequences (61.7 Mb) from 15 species of hares (1–4 individuals per species), spanning the global distribution of the genus, and two outgroups. We used a coalescent framework to infer species relationships and divergence times, despite extensive genealogical discordance. We found high levels of allele sharing among species and show that this reflects extensive incomplete lineage sorting and temporally layered hybridization. Our results revealed recurrent introgression at all stages along the Lepus radiation, including recent gene flow between extant species since the last glacial maximum but also pervasive ancient introgression occurring since near the origin of the hare lineages. We show that ancient hybridization between northern hemisphere species has resulted in shared variation of potential adaptive relevance to highly seasonal environments, including genes involved in circadian rhythm regulation, pigmentation, and thermoregulation. Our results illustrate how the genetic legacy of ancestral hybridization may persist across a radiation, leaving a long-lasting signature of shared genetic variation that may contribute to adaptation.
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| 2. |
- Mucci, Nadia, et al.
(författare)
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Genetic diversity and landscape genetic structure of otter (Lutra lutra) populations in Europe
- 2010
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Ingår i: Conservation Genetics. - : Springer Science and Business Media LLC. - 1566-0621 .- 1572-9737. ; 11:2, s. 583-599
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Tidskriftsartikel (refereegranskat)abstract
- Eurasian otter populations strongly declined and partially disappeared due to global and local causes (habitat destruction, water pollution, human persecution) in parts of their continental range. Conservation strategies, based on reintroduction projects or restoration of dispersal corridors, should rely on sound knowledge of the historical or recent consequences of population genetic structuring. Here we present the results of a survey performed on 616 samples, collected from 19 European countries, genotyped at the mtDNA control-region and 11 autosomal microsatellites. The mtDNA variability was low (nucleotide diversity = 0.0014; average number of pairwise differences = 2.25), suggesting that extant otter mtDNA lineages originated recently. A star-shaped mtDNA network did not allow outlining any phylogeographic inference. Microsatellites were only moderately variable (H (o) = 0.50; H (e) = 0.58, on average across populations), the average allele number was low (observed A (o) = 4.9, range 2.5-6.8; effective A (e) = 2.8; range 1.6-3.7), suggesting small historical effective population size. Extant otters likely originated from the expansion of a single refugial population. Bayesian clustering and landscape genetic analyses however indicate that local populations are genetically differentiated, perhaps as consequence of post-glacial demographic fluctuations and recent isolation. These results delineate a framework that should be used for implementing conservation programs in Europe, particularly if they are based on the reintroduction of wild or captive-reproduced otters.
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