Levänen Riikka, Thulin Carl-Gustaf, Spong Göran, Pohjoismäki Jaakko L O
Department of Environmental and Biological Sciences, University of Eastern Finland, Joensuu, Finland.
Molecular Ecology Group, Department of Wildlife, Fish, and Environmental Studies, Swedish University of Agricultural Sciences, Umeå, Sweden.
PLoS One. 2018 Jan 25;13(1):e0191790. doi: 10.1371/journal.pone.0191790. eCollection 2018.
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 low 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.
在斯堪的纳维亚半岛，山兔（Lepus timidus）和棕兔（Lepus europaeus）杂交并产生可育后代，导致基因跨越物种屏障流动。对母系遗传的线粒体DNA（mtDNA）的分析表明，基因渗入频繁发生，但由于缺乏合适的核DNA标记，难以评估其对物种的规模和意义。随着棕兔的分布范围不断向北扩展，显然是以山兔为代价，基因渗入的程度变得至关重要，这引发了对可能存在的竞争的担忧。我们在此报告，基于对6833个单核苷酸多态性（SNP）标记的分析，基因流动方向上山兔到棕兔的基因渗入是高度不对称的，并且核基因渗入水平与mtDNA渗入无关。虽然棕兔有可能从当地的山兔那里获得适应性等位基因，但异域分布的棕兔中山兔等位基因水平较低，这表明杂交是由随机过程驱动的。在斯堪的纳维亚半岛，与棕兔的种间基因流动不太可能对山兔产生重大影响，但直接竞争可能会有影响。
