Experimental hybridization studies suggest that pleiotropic alleles commonly underlie adaptive divergence between natural populations

If adaptation typically involves pleiotropy and compensation, then the segregation variance for traits under stabilizing selection is expected to increase with the magnitude of adaptive phenotypic divergence between parents. This prediction has not been tested empirically, and I gathered data from experimental hybridization studies to evaluate it. I found that pairs of parents which are more phenotypically divergent beget hybrids with more segregation variance in traits for which the parents are statistically indistinguishable.

This result suggests that adaptive divergence between pairs of natural populations proceeds via pleiotropy and compensation, and that deleterious transgressive segregation variance accumulates systematically as populations diverge.

Methods

Please see detailed description in appendix of article.