Discordant divergence times among Z-chromosome regions between two ecologically distinct swallowtail butterfly species

作者：Putnam Andrea S^*; Scriber J Mark; Andolfatto Peter

来源：Evolution, 2007, 61(4): 912-927.

DOI：10.1111/j.1558-5646.2007.00076.x

• approximate Bayesian computation
• divergence
• hybrid zones
• introgression
• Lepidoptera
• Papilio
• speciation

We investigate multi locus patterns of differentiation between parental populations of two swallowtail butterfly species that differ at a number of ecologically important sex-linked traits. Using a new coalescent-based approach, we show that there is significant heterogeneity in estimated divergence times among five Z-linked markers, rejecting a purely allopatric speciation model. We infer that the Z chromosome is a mosaic of regions that differ in the extent of historical gene flow, potentially due to isolating barriers that prevent the introgression of species-specific traits that result in hybrid incompatibilities. Surprisingly, a candidate region for a strong barrier to introgression, Ldh, does not show a significantly deeper divergence time than other markers on the Z chromosome. Our approach can be used to test alternative models of speciation and can potentially assign chronological order to the appearance of factors contributing to reproductive isolation between species.

• 出版日期2007-4