Yannic G, Basset P, Hausser J
Department of Ecology and Evolution, Biology Building, University of Lausanne, CH-1015 Lausanne, Switzerland.
Mol Phylogenet Evol. 2008 Apr;47(1):237-50. doi: 10.1016/j.ympev.2008.01.029. Epub 2008 Feb 2.
The species of the common shrew (Sorex araneus) group are morphologically very similar, but have undergone a spectacular chromosomal evolution. We investigate here the evolutionary history of the Sorex araneus group distributed in western Europe. In particular, we clarify the position of a difficult species, S. granarius, using sex-specific (mtDNA and Y-chromosome) markers. The karyotype of S. granarius is generally considered similar to the common ancestor of the restricted group considered here. The mtDNA data (1.4 kb) confirms the close relationship between S. granarius and S. araneus sensu stricto (hereafter S. araneus s.s.), but the Y-chromosome (3.4 kb) produces a quite different picture: S. granarius is closely related to another species, S. coronatus. Comparison of mtDNA and Y-chromosome phylogenies suggests that the genetic and chromosomal evolution in this group are disconnected processes. The evolutionary history of the south-western European populations of the S. araneus group can only be understood considering secondary contacts between taxa after their divergence, implying genetic exchanges by means of hybridization and/or introgression.
普通鼩鼱（Sorex araneus）群体中的物种在形态上非常相似，但经历了显著的染色体进化。我们在此研究分布于西欧的普通鼩鼱群体的进化历史。特别是，我们使用性别特异性（线粒体DNA和Y染色体）标记来阐明一个难以界定的物种——粒形鼩鼱（S. granarius）的分类地位。粒形鼩鼱的核型通常被认为与这里所考虑的狭义群体的共同祖先相似。线粒体DNA数据（1.4 kb）证实了粒形鼩鼱与狭义普通鼩鼱（以下简称普通鼩鼱s.s.）之间的密切关系，但Y染色体（3.4 kb）呈现出截然不同的情况：粒形鼩鼱与另一个物种——冠鼩鼱（S. coronatus）密切相关。线粒体DNA和Y染色体系统发育的比较表明，该群体中的遗传和染色体进化是相互独立的过程。只有考虑到分类群分化后的二次接触，即通过杂交和/或基因渗入进行的基因交换，才能理解普通鼩鼱群体在西南欧种群的进化历史。
