Basset P, Yannic G, Hausser J
Department of Ecology and Evolution, University of Lausanne, Switzerland.
Mol Ecol. 2006 May;15(6):1577-87. doi: 10.1111/j.1365-294X.2006.02891.x.
The species of the common shrew (Sorex araneus) group are morphologically very similar but exhibit high levels of karyotypic variation. Here we used genetic variation at 10 microsatellite markers in a data set of 212 individuals mostly sampled in the western Alps and composed of five karyotypic taxa (Sorex coronatus, Sorex antinorii and the S. araneus chromosome races Cordon, Bretolet and Vaud) to investigate the concordance between genetic and karyotypic structure. Bayesian analysis confirmed the taxonomic status of the three sampled species since individuals consistently grouped according to their taxonomical status. However, introgression can still be detected between S. antinorii and the race Cordon of S. araneus. This observation is consistent with the expected low karyotypic complexity of hybrids between these two taxa. Geographically based cryptic substructure was discovered within S. antinorii, a pattern consistent with the different postglaciation recolonization routes of this species. Additionally, we detected two genetic groups within S. araneus notwithstanding the presence of three chromosome races. This pattern can be explained by the probable hybrid status of the Bretolet race but also suggests a relatively low impact of chromosomal differences on genetic structure compared to historical factors. Finally, we propose that the current data set (available at http://www.unil.ch/dee/page7010_en.html#1) could be used as a reference by those wanting to identify Sorex individuals sampled in the western Alps.
普通鼩鼱（Sorex araneus）群体中的物种在形态上非常相似，但核型变异水平较高。在此，我们利用212个个体的10个微卫星标记的遗传变异，这些个体大多采自西阿尔卑斯山，由五个核型分类单元（Sorex coronatus、Sorex antinorii以及S. araneus染色体族系Cordon、Bretolet和Vaud）组成，以研究遗传结构与核型结构之间的一致性。贝叶斯分析证实了三个采样物种的分类地位，因为个体根据其分类地位始终聚类。然而，仍可检测到S. antinorii与S. araneus的Cordon族系之间存在基因渗入。这一观察结果与这两个分类单元之间杂种预期的低核型复杂性一致。在S. antinorii中发现了基于地理的隐秘亚结构，这一模式与该物种不同的冰期后重新定殖路线一致。此外，尽管存在三个染色体族系，但我们在S. araneus中检测到两个遗传群体。这种模式可以用Bretolet族系可能的杂种状态来解释，但也表明与历史因素相比，染色体差异对遗传结构的影响相对较小。最后，我们建议当前的数据集（可在http://www.unil.ch/dee/page7010_en.html#1获取）可供那些想要鉴定在西阿尔卑斯山采样的鼩鼱个体的人作为参考。
