Drovetski Sergei V, Semenov Georgy, Red'kin Yaroslav A, Sotnikov Vladimir N, Fadeev Igor V, Koblik Evgeniy A
Department of Natural History, Tromsø University Museum, University of Tromsø-The Arctic University of Norway, Tromsø, Norway.
Thematic Group on Bird Ecology, Institute of Systematics and Ecology of Animals of Siberian Branch of Russian Academy of Sciences, Novosibirsk, Russia.
PLoS One. 2015 Apr 7;10(4):e0122590. doi: 10.1371/journal.pone.0122590. eCollection 2015.
When isolated but reproductively compatible populations expand geographically and meet, simulations predict asymmetric introgression of neutral loci from a local to invading taxon. Genetic introgression may affect phylogenetic reconstruction by obscuring topology and divergence estimates. We combined phylogenetic analysis of sequences from one mtDNA and 12 nuDNA loci with analysis of gene flow among 5 species of Pacific Locustella warblers to test for presence of genetic introgression and its effects on tree topology and divergence estimates. Our data showed that nuDNA introgression was substantial and asymmetrical among all members of superspecies groups whereas mtDNA showed no introgression except a single species pair where the invader's mtDNA was swept by mtDNA of the local species. This introgressive sweep of mtDNA had the opposite direction of the nuDNA introgression and resulted in the paraphyly of the local species' mtDNA haplotypes with respect to those of the invader. Тhe multilocus nuDNA species tree resolved all inter- and intraspecific relationships despite substantial introgression. However, the node ages on the species tree may be underestimated as suggested by the differences in node age estimates based on non-introgressing mtDNA and introgressing nuDNA. In turn, the introgressive sweep and strong purifying selection appear to elongate internal branches in the mtDNA gene tree.
当孤立但生殖兼容的种群在地理上扩张并相遇时，模拟预测中性基因座会从本地分类群向入侵分类群进行不对称渐渗。基因渐渗可能会通过模糊拓扑结构和分歧估计来影响系统发育重建。我们将对一个线粒体DNA（mtDNA）和12个核DNA（nuDNA）基因座的序列进行系统发育分析，与对5种太平洋蝗莺之间的基因流分析相结合，以测试基因渐渗的存在及其对树形拓扑结构和分歧估计的影响。我们的数据表明，在超物种组的所有成员中，核DNA渐渗是大量且不对称的，而线粒体DNA除了一个单一物种对中入侵者的线粒体DNA被本地物种的线粒体DNA取代外，没有显示出渐渗现象。这种线粒体DNA的渐渗取代与核DNA渐渗方向相反，导致本地物种线粒体DNA单倍型相对于入侵者的单倍型出现并系现象。尽管存在大量渐渗，多位点核DNA物种树仍解析了所有种间和种内关系。然而，正如基于非渐渗的线粒体DNA和渐渗的核DNA的节点年龄估计差异所表明的那样，物种树上的节点年龄可能被低估了。反过来，渐渗取代和强烈的纯化选择似乎延长了线粒体DNA基因树中的内部分支。
