Good Jeffrey M, Dean Matthew D, Nachman Michael W
Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona 85721, USA.
Genetics. 2008 Aug;179(4):2213-28. doi: 10.1534/genetics.107.085340. Epub 2008 Aug 9.
The X chromosome plays a central role in the evolution of reproductive isolation, but few studies have examined the genetic basis of X-linked incompatibilities during the early stages of speciation. We report the results of a large experiment focused on the reciprocal introgression of the X chromosome between two species of house mice, Mus musculus and M. domesticus. Introgression of the M. musculus X chromosome into a wild-derived M. domesticus genetic background produced male-limited sterility, qualitatively consistent with previous experiments using classic inbred strains to represent M. domesticus. The genetic basis of sterility involved a minimum of four X-linked factors. The phenotypic effects of major sterility QTL were largely additive and resulted in complete sterility when combined. No sterility factors were uncovered on the M. domesticus X chromosome. Overall, these results revealed a complex and asymmetric genetic basis to X-linked hybrid male sterility during the early stages of speciation in mice. Combined with data from previous studies, we identify one relatively narrow interval on the M. musculus X chromosome involved in hybrid male sterility. Only a handful of spermatogenic genes are within this region, including one of the most rapidly evolving genes on the mouse X chromosome.
X染色体在生殖隔离的进化过程中起着核心作用，但很少有研究在物种形成的早期阶段研究X连锁不相容性的遗传基础。我们报告了一项大型实验的结果，该实验聚焦于家鼠两个物种——小家鼠（Mus musculus）和家鼠（M. domesticus）之间X染色体的相互渗入。将小家鼠的X染色体渗入野生型家鼠的遗传背景中会导致雄性特异性不育，这与之前使用经典近交系代表家鼠进行的实验结果在性质上是一致的。不育的遗传基础至少涉及四个X连锁因子。主要不育数量性状位点的表型效应在很大程度上是累加性的，并且组合在一起时会导致完全不育。在家鼠的X染色体上未发现不育因子。总体而言，这些结果揭示了小鼠物种形成早期阶段X连锁杂种雄性不育的复杂且不对称的遗传基础。结合之前研究的数据，我们在小家鼠的X染色体上确定了一个与杂种雄性不育有关的相对狭窄的区间。该区域内只有少数几个生精基因，包括小鼠X染色体上进化最快的基因之一。
