Dipartimento di Biologia Animale e dell'Uomo, University of Rome La Sapienza, Via A. Borelli 50, 00161 Rome, Italy.
Evolution. 2010 Jul;64(7):2020-32. doi: 10.1111/j.1558-5646.2010.00964.x. Epub 2010 Feb 9.
The West European house mouse, Mus musculus domesticus, is a particularly suitable model to investigate the role of chromosomal rearrangements in reproductive isolation. In fact, it exhibits a broad range of chromosomal polymorphism due to Robertsonian (Rb) fusions leading to various types of contact zones between different chromosomal races. In the present study, we analyzed a parapatric contact in central Italy between the Cittaducale chromosomal race (CD: 2n= 22) and the surrounding populations with standard karyotype (2n= 40) to understand if Rb fusions play a causative role in speciation. One hundred forty-seven mice from 17 localities were genotyped by means of 12 microsatellite loci. A telomeric and a pericentromeric locus situated on six chromosome arms (four Rbs and one telocentric) were selected to detect differences in the amount of gene flow for each locus in different chromosomal positions. The analyses performed on the two subsets of loci show differences in the level of gene flow, which is more restricted near the centromeres of Rb chromosomes. This effect is less pronounced in the homozygotes populations settled at the border of the hybrid zone. We discuss the possible cause of the differential porosity of gene flow in Rbs considering "hybrid dysfunctions" and "suppressed recombination" models.
西欧家鼠（Mus musculus domesticus）是研究染色体重排在生殖隔离中作用的特别合适的模型。事实上，由于罗伯逊易位（Rb）融合导致不同染色体种族之间存在各种类型的接触区，它表现出广泛的染色体多态性。在本研究中，我们分析了意大利中部的一个边缘接触区，即奇塔杜卡莱染色体种族（CD：2n=22）与周围具有标准核型（2n=40）的种群之间的关系，以了解 Rb 融合是否在物种形成中起因果作用。通过 12 个微卫星基因座，对来自 17 个地点的 147 只老鼠进行了基因型分析。选择了位于 6 条染色体臂上的一个端粒和一个着丝粒周围的基因座（4 个 Rb 和一个着丝粒），以检测每个基因座在不同染色体位置的基因流量差异。对这两个基因座子集的分析显示，基因流的水平存在差异，在 Rb 染色体的着丝粒附近受到的限制更为明显。这种效应在杂交区边界定居的纯合种群中不太明显。我们讨论了在 Rb 中基因流的差异渗透性的可能原因，考虑了“杂种功能障碍”和“抑制重组”模型。
