Museum of Zoology, University of Michigan, Ann Arbor, Michigan 48109, USA.
Evolution. 2010 Feb 1;64(2):472-85. doi: 10.1111/j.1558-5646.2009.00846.x. Epub 2009 Sep 30.
Studies of the genetics of hybrid zones can provide insight into the genomic architecture of species boundaries. By examining patterns of introgression of multiple loci across a hybrid zone, it may be possible to identify regions of the genome that have experienced selection. Here, we present a comparison of introgression in two replicate transects through the house mouse hybrid zone through central Europe, using data from 41 single nucleotide markers. Using both genomic and geographic clines, we found many differences in patterns of introgression between the two transects, as well as some similarities. We found that many loci may have experienced the effects of selection at linked sites, including selection against hybrid genotypes, as well as positive selection in the form of genotypes introgressed into a foreign genetic background. We also found many positive associations of conspecific alleles among unlinked markers, which could be caused by epistatic interactions. Different patterns of introgression in the two transects highlight the challenge of using hybrid zones to identify genes underlying isolation and raise the possibility that the genetic basis of isolation between these species may be dependent on the local population genetic make-up or the local ecological setting.
杂交区的遗传学研究可以深入了解物种界限的基因组结构。通过研究多个基因座在杂交区的渐渗模式，有可能确定经历了选择的基因组区域。在这里，我们使用来自 41 个单核苷酸标记的数据，比较了通过中欧家鼠杂交区的两个重复横断面的渐渗情况。利用基因组和地理渐变，我们发现两个横断面之间的渐渗模式有许多差异，也有一些相似之处。我们发现，许多基因座可能经历了连锁位点选择的影响，包括对杂种基因型的选择，以及以导入外来遗传背景的基因型的形式的正选择。我们还发现，许多不相关标记之间的同种等位基因存在正关联，这可能是由上位性相互作用引起的。两个横断面的不同渐渗模式突出了利用杂交区来识别隔离的基因的挑战，并提出了这些物种之间隔离的遗传基础可能取决于当地种群遗传结构或当地生态环境的可能性。
