Mackiewicz Paweł, Moska Magdalena, Wierzbicki Heliodor, Gagat Przemysław, Mackiewicz Dorota
Department of Genomics, Faculty of Biotechnology, University of Wrocław, Wrocław, Poland.
Department of Genetics, Wroclaw University of Environmental and Life Sciences, Wroclaw, Poland.
PLoS One. 2017 Jun 26;12(6):e0179760. doi: 10.1371/journal.pone.0179760. eCollection 2017.
Shrews of the Sorex genus are an evolutionarily successful group that includes more than 77 species widely distributed in Eurasia and North America. The genus is one of the rare cases where karyotypic changes reflect well the evolutionary relationships among its species. The taxa showing the greatest variation in karyotype are usually classified into the Sorex araneus group. Its evolution was associated with chromosomal rearrangements, which could have promoted fast diversification of this group into many chromosomal races and species. These processes were additionally complicated by introgressions of mitochondrial DNA, which made the evolutionary history of this group quite complex and difficult to infer. To tackle the problem, we performed multi-method phylogenetic analyses based on mitochondrial cytochrome b that is considered a good molecular marker available for many representatives of Sorex. The results were compared with phylogenies based on chromosomal rearrangement data and put into temporal and spatial context using molecular dating and historical biogeography methods. We complemented the study with the estimation of diversification rates within the S. araneus group as well as comparing the results with paleontological records and climatic oscillations within the last 4 million years. Based on the gathered data, we proposed a hypothetical scenario for the evolution and geographic dispersion of species belonging to the S. araneus group. The shrews began to diversify about 2.7 million years ago in Eurasia and then migrated at least twice to North America. The evolution of shrews was driven by Pleistocene glacial and interglacial cycles, which increased their speciation rate and the emergence of new lineages. The migrations of populations were accompanied by introgressions of mitochondrial DNA into native shrews and occurred at least twice.
鼩鼱属的鼩鼱是一个进化上很成功的类群，包括77种以上，广泛分布于欧亚大陆和北美洲。该属是核型变化很好地反映其物种间进化关系的罕见案例之一。核型变化最大的分类群通常被归入普通鼩鼱组。其进化与染色体重排有关，这可能促进了该类群快速分化为许多染色体族和物种。线粒体DNA的渗入使这些过程更加复杂，这使得该类群的进化历史相当复杂且难以推断。为了解决这个问题，我们基于线粒体细胞色素b进行了多方法系统发育分析，线粒体细胞色素b被认为是一种适用于许多鼩鼱属代表物种的良好分子标记。将结果与基于染色体重排数据的系统发育进行比较，并使用分子年代测定和历史生物地理学方法将其置于时间和空间背景中。我们通过估计普通鼩鼱组内的多样化速率，并将结果与过去400万年的古生物学记录和气候振荡进行比较，对该研究进行了补充。基于收集到的数据，我们提出了一个关于普通鼩鼱组物种进化和地理扩散的假设情景。鼩鼱大约在270万年前在欧亚大陆开始分化，然后至少两次迁移到北美洲。鼩鼱的进化是由更新世冰期和间冰期循环驱动的，这增加了它们的物种形成速率和新谱系的出现。种群迁移伴随着线粒体DNA渗入本地鼩鼱，并且至少发生了两次。
