Data from: Selfish evolution of cytonuclear hybrid incompatibility in (Mimulus)

Intraspecific co-evolution between selfish elements and suppressors may promote interspecific hybrid incompatibility, but evidence of this process is rare. Here, we use genomic data to test alternative models for the evolution of cytonuclear hybrid male sterility in (Mimulus). In hybrids between Iron Mountain (IM) (M. guttatus x M. nasutus), two tightly linked <i>M. guttatus</i> alleles (<i>Rf</i>1/<i>Rf</i>2) each restore male fertility by suppressing a local mitochondrial male-sterility gene (IM-CMS). Unlike neutral models for the evolution of hybrid incompatibility loci, selfish evolution predicts that the <i>Rf</i> alleles experienced strong selection in the presence of IM-CMS. Using whole genome sequences, we compared patterns of population-genetic variation in (Rf) at IM to a neighboring population that lacks IM-CMS. Consistent with local selection in the presence of IM-CMS, the <i>Rf</i> region shows elevated <i>F</i>_ST, high local linkage disequilibrium and a distinct haplotype structure at IM, but not at CP, suggesting a recent sweep in the presence of IM-CMS. In both populations, <i>Rf</i>2 exhibited lower polymorphism than other regions, but the low diversity outliers were different between CP and IM. Our results confirm theoretical predictions of ubiquitous cytonuclear conflict in plants and provide a population-genetic mechanism for the evolution of a common form of hybrid incompatibility.