Discordant Phylogeographic Patterns Between the Y Chromosome and Mitochondrial DNA in the House Mouse: Selection on the Y Chromosome?

[摘要] We have compared patterns of geographic variation and molecular divergence of mitochondrial DNA (mtDNA) and Y chromosome over the range of the different subspecies of Mus musculus. MtDNA was typed for 305 nucleotides in the control region, the Y chromosome for 834 base pairs (bp) in Zfy introns and 242 bp in Sry , a Zfy2 18-bp deletion, and two microsatellites. Apparent discrepancies exist between the distributions of the lineages of mtDNA and of the two major Y -chromosome lineages thus defined: some subspecies share the same mtDNA lineage but have different Y -chromosome lineages or vice versa. One microsatellite reveals a geographically clustered variation inside the distribution of each Y -chromosome lineage, showing that new Y -chromosome variants can rapidly spread locally. The two major Y -chromosome lineages have a divergence time only about one fourth of that between mtDNA lineages. Although this recent coalescence of the Y chromosomes between subspecies could partly be due to a lower ancestral polymorphism of the Y chromosome, it suggests that secondary introgression after the radiation of the subspecies might have occurred. There is evidence that the differentiation of the Y -chromosome lineages contributes to partial reproductive isolation between subspecies, and patterns of molecular evolution suggest that selection has played a role in the rapid spread across subspecies.

[学科分类] 医学（综合）