View Program - 2022 Population, Evolutionary, and Quantitative Genetics Conference

Reproductive isolation between divergent populations is often the result of deleterious epistatic interactions between their genetic differences. Not all fixed differences contribute equally to reproductive isolation, however, since loci across the genome vary in their number of gene interactions. We consider how this variation in connectivity affects the accumulation of hybrid incompatibilities between allopatric populations, using computer simulations of substitutions on a scale-free network in which highly connected genes were assigned lower substitution rates (mimicking the effect of selective constraint on hub genes). These results are compared to: (1) uniform substitution rates and (2) varied substitution rates that are random with respect to connectivity. We find that greater variation in negative selection slows the rate of incompatibility accumulation and delays the complexification process by which incompatibilities agglomerate on the gene network.

Accumulation of hybrid incompatibilities on scale-free networks with purifying selection