A genomic footprint of hybrid zone movement in crested newts

Speciation typically involves a stage in which species can still exchange genetic material. Interspecific gene flow is facilitated by the hybrid zones that such species establish upon secondary contact. If one member of a hybridizing species pair displaces the other, their hybrid zone would move across the landscape. Although theory predicts that moving hybrid zones quickly stagnate, hybrid zones tracked over one or a few decades do not always follow such a limitation. This suggests that hybrid zones have the potential to traverse considerable distances over extended periods of time. When hybrid zones move, introgression is predicted to result in biased gene flow of selectively neutral alleles, from the receding species into the advancing species. We test for such a genomic footprint of hybrid zone movement in a pair of crested newt species (genus Triturus) for which we have a priori support for westward hybrid zone movement. We perform a multilocus phylogeographical survey and conduct ...物种形成（speciation）过程通常存在一个阶段，此时不同物种仍可发生遗传物质交换。这类物种在次生接触（secondary contact）后形成的杂交带（hybrid zone），可促进种间基因流（interspecific gene flow）。若一对杂交物种中的一方取代另一方，其杂交带便会在地理范围内移动。尽管理论预测移动的杂交带会迅速停滞，但数十年或数年内追踪到的杂交带往往并不受此限制，这表明杂交带在较长时间跨度内具备长距离移动的潜力。当杂交带移动时，基因渐渗（introgression）会导致选择中性等位基因（selectively neutral alleles）从后退物种向前进物种发生偏态基因流。我们以一对冠螈属（Triturus）物种为研究对象，该类群已有先验证据支持其杂交带存在西向移动现象，将开展多位点谱系地理学调查（phylogeographical survey）并进行……