Data from: Widespread introgression of mountain hare genes into Fennoscandian brown hare populations

In Fennoscandia, mountain hare (Lepus timidus) and brown hare (Lepus europaeus) hybridize and produce fertile offspring, resulting in gene flow across the species barrier. Analyses of maternally inherited mitochondrial DNA (mtDNA) show that introgression occur frequently, but unavailability of appropriate nuclear DNA markers has made it difficult to evaluate the scale- and significance for the species. The extent of introgression has become important as the brown hare is continuously expanding its range northward, at the apparent expense of the mountain hare, raising concerns about possible competition. We report here, based on analysis of 6833 SNP markers, that the introgression is highly asymmetrical in the direction of gene flow from mountain hare to brown hare, and that the levels of nuclear gene introgression are independent of mtDNA introgression. While it is possible that brown hares obtain locally adapted alleles from the resident mountain hares, the lower levels of mountain hare alleles among allopatric brown hares suggest that hybridization is driven by stochastic processes. Interspecific geneflow with the brown hare is unlikely to have major impacts on mountain hare in Fennoscandia, but direct competition may.在芬诺斯坎底亚地区，雪兔（Lepus timidus）与欧洲棕兔（Lepus europaeus）会发生杂交并产生可育后代，进而形成跨越物种屏障的基因交流。针对母系遗传的线粒体DNA（mtDNA）的分析显示，基因渐渗现象频繁发生，但由于缺乏合适的核DNA标记，难以评估该现象的发生规模及其对两个物种种群的意义。随着欧洲棕兔持续向北扩张其分布范围，且这一过程似乎以雪兔的生存为代价，基因渐渗的程度愈发受到关注，相关研究也引发了对二者潜在种间竞争的担忧。本研究基于对6833个单核苷酸多态性（SNP）标记的分析，发现基因渐渗具有高度不对称性：基因流主要从雪兔流向欧洲棕兔，且核基因渐渗水平与线粒体DNA渐渗水平相互独立。尽管欧洲棕兔有可能从定居的雪兔种群中获取本地适应性等位基因，但异域分布的欧洲棕兔种群中雪兔等位基因的频率较低，这表明杂交事件主要由随机过程驱动。在芬诺斯坎底亚地区，欧洲棕兔与雪兔之间的种间基因交流不太可能对雪兔种群造成显著影响，但二者的直接竞争则可能产生重大后果。