Brändli Laura, Handley Lori-Jayne Lawson, Vogel Peter, Perrin Nicolas
Department of Ecology and Evolution, University of Lausanne, Biology Building, CH-1015 Lausanne, Switzerland.
Mol Phylogenet Evol. 2005 Dec;37(3):832-44. doi: 10.1016/j.ympev.2005.06.019. Epub 2005 Aug 10.
We investigate the evolutionary history of the greater white-toothed shrew across its distribution in northern Africa and mainland Europe using sex-specific (mtDNA and Y chromosome) and biparental (X chromosome) markers. All three loci confirm a large divergence between eastern (Tunisia and Sardinia) and western (Morocco and mainland Europe) lineages, and application of a molecular clock to mtDNA divergence estimates indicates a more ancient separation (2.25 M yr ago) than described by some previous studies, supporting claims for taxonomic revision. Moroccan ancestry for the mainland European population is inconclusive from phylogenetic trees, but is supported by greater nucleotide diversity and a more ancient population expansion in Morocco than in Europe. Signatures of rapid population expansion in mtDNA, combined with low X and Y chromosome diversity, suggest a single colonization of mainland Europe by a small number of Moroccan shrews >38 K yr ago. This study illustrates that multilocus genetic analyses can facilitate the interpretation of species' evolutionary history but that phylogeographic inference using X and Y chromosomes is restricted by low levels of observed polymorphism.
我们使用性别特异性（线粒体DNA和Y染色体）及双亲（X染色体）标记，研究了北非和欧洲大陆分布范围内的大白齿鼩的进化历史。所有这三个基因座都证实了东部（突尼斯和撒丁岛）和西部（摩洛哥和欧洲大陆）谱系之间存在很大差异，并且将分子钟应用于线粒体DNA差异估计表明，其分离时间比一些先前研究描述的更为古老（225万年前），这支持了分类学修订的主张。从系统发育树来看，欧洲大陆种群的摩洛哥血统尚无定论，但摩洛哥比欧洲具有更高的核苷酸多样性和更古老的种群扩张，这为其提供了支持。线粒体DNA中快速种群扩张的特征，再加上X和Y染色体多样性较低，表明3.8万多年前有少量摩洛哥鼩鼱对欧洲大陆进行了单次殖民。这项研究表明，多基因座遗传分析有助于解释物种的进化历史，但使用X和Y染色体进行系统地理学推断受到观察到的多态性水平较低的限制。
