Population genomic signatures of founding events in autonomously self-fertilizing plants: a test with Impatiens capensis.

Autonomously self-fertilizing plants possess disproportionate abilities to found populations. Viewed from the metapopulation perspective, founding events should be frequent in such plants, but the intensity and timing of bottlenecks and recovery should vary among populations. We tested the hypothesis that variation in these demographic characteristics in one such species helps to explain variation in levels of genetic diversity and population genomic signatures of inbreeding, relative recombination, and microscale spatial genetic structure. We used reduced-representation sequence data from 11 populations of the dimorphic cleistogamous (CL) species Impatiens capensis, a species that has figured prominently in evolutionary studies. The populations occur in a landscape where suitable habitat is fragmented. Population genomic analyses revealed significant among-population variation in demographic history, genetic diversity, inbreeding, relative recombination, tracts of homozygosity by descent, and spatial autocorrelation of genotypes at microgeographic scale Our findings support the hypothesis that variation in the intensity of bottlenecks and length of the postbottleneck recovery phase in autonomously self-fertilizing plants leads to variation in genetic diversity and a suite of associated population genomic signatures of inbreeding. We suggest that these findings have consequences for understanding evolutionary processes and guiding conservation strategies in fragmented habitats for dimorphic CL species.