Data from: Bayesian analysis of hybridization and introgression between the endangered european mink (Mustela lutreola) and the polecat (Mustela putorius)

Human-mediated global change will probably increase the rates of natural hybridization and genetic introgression between closely related species, and this will have major implications for conservation of the taxa involved. In this study, we analyse both mitochondrial and nuclear data to characterize ongoing hybridization and genetic introgression between two sympatric sister species of mustelids, the endangered European mink (Mustela lutreola) and the more abundant polecat (M. putorius). A total of 317 European mink, 114 polecats and 15 putative hybrid individuals were collected from different localities in Europe and genotyped with 13 microsatellite nuclear markers. Recently developed Bayesian methods for assigning individuals to populations and identifying admixture proportions were applied to the genetic data. To identify the direction of hybridization, we additionally sequenced mtDNA and Y chromosomes from 78 individuals and 29 males respectively. We found that both hybridization and genetic introgression occurred at low levels (3% and 0.9% respectively) and indicated that hybridization is asymmetric, as only pure polecat males mate with pure European mink females. Furthermore, backcrossing and genetic introgression was detected only from female first-generation (F1) hybrids of European mink to polecats. This latter result implies that Haldane’s rule may apply. Our results suggest that hybridization and genetic introgression between the two species should be considered a rather uncommon event. However, the current low densities of European mink might be changing this trend.

人类活动驱动的全球变化或会提升近缘物种间自然杂交（natural hybridization）与遗传渐渗（genetic introgression）的速率，这对相关类群的保护工作具有深远影响。本研究通过解析线粒体与核基因组数据，对两种同域分布的鼬科动物（mustelids）姊妹物种——濒危的欧洲水鼬（Mustela lutreola）与种群更为繁盛的普通艾鼬（Mustela putorius）之间正在发生的杂交与遗传渐渗过程进行了表征。研究团队共采集了分布于欧洲不同地域的317只欧洲水鼬、114只普通艾鼬以及15只疑似杂交个体，利用13个核微卫星标记（microsatellite nuclear markers）对其进行基因分型。本研究采用新近开发的贝叶斯方法（Bayesian methods）开展个体种群归属判定与混杂比例（admixture proportions）估算，并将其应用于遗传数据分析。为明确杂交方向，研究团队额外对78个个体的线粒体DNA（mtDNA）以及29只雄性个体的Y染色体（Y chromosomes）进行了测序。结果显示，杂交与遗传渐渗的发生水平均较低（分别为3%与0.9%），且杂交模式存在不对称性：仅纯种普通艾鼬雄性可与纯种欧洲水鼬雌性交配。此外，回交（backcrossing）与遗传渐渗仅在源自欧洲水鼬的雌性第一代（F1）杂交个体（first-generation (F1) hybrids）与普通艾鼬之间被检测到，这一结果提示霍尔丹法则（Haldane’s rule）可能适用于该物种对。本研究结果表明，两物种间的杂交与遗传渐渗属于较为罕见的事件，但当前欧洲水鼬种群密度偏低的现状或许正在改变这一趋势。