Speciation is a primary determinant of biodiversity. Dissecting the genetics of reproductive barriers between closely related species can reveal mechanisms of speciation. Empirical and theoretical work suggest that reductions in the fitness of interspecific hybrids are disproportionately caused by deleterious epistatic interactions between genes. An influential but rarely tested prediction is that these hybrid incompatibilities should accumulate faster than linearly (“snowball”) with divergence time. To test this prediction, we identified quantitative trait loci (QTL) that cause hybrid sterility in crosses between subspecies of house mice. We developed a comparative method that uses patterns of incompatibility sharing between species pairs to evaluate competing genetic models of speciation. Application of this method indicated that hybrid sterility loci in house mice evolved according to the snowball model. Our results demonstrate the power of combining genetic and phylogenetic frameworks for understanding speciation.
Coffee and cookies will be served at 4 p.m.
Host: Professor Patricia Wittkopp
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