Genomics of Speciation in Mimulus

The plant genus Mimulus contains ~160 species, has been a model for evolutionary ecology for over fifty years. The genus hosts a diverse array of mating systems, pollinator syndromes, habitat preferences and other adaptations, often between closely related species. The short generation time, small size, compact genome, self-compatibility, high fecundity, and ease of cultivation and crossability allow investigators to easily dissect the genetic basis for these traits.

As part of a large collaborative effort, we are developing genomic resources for Mimulus and applying these same tools to study the molecular basis of reproductive isolation and species differences between several closely related members of the genus. The genomic resources that we have been or are developing in Mimulus include expressed sequence tags, gene-based markers, saturated genetic maps, integrated physical maps based on large-insert clones that have been fingerprinted, end-sequenced and probed with markers on the genetic map, and permanent QTL mapping populations.

Using these resources, we are investigating the molecular basis of the hybrid incompatibility systems in the guttatus x nasutus cross, and the adaptive differentiation in pollination syndrome seen in the lewisii x cardinalis cross. We are undertaking studies of the molecular evolution and population genetics of the loci contributing to reproductive isolation and adaptively important species differences.