RT Journal Article SR Electronic T1 Speciation and introgression between Mimulus nasutus and Mimulus guttatus JF bioRxiv FD Cold Spring Harbor Laboratory SP 000109 DO 10.1101/000109 A1 Yaniv Brandvain A1 Amanda M. Kenney A1 Lex Flagel A1 Graham Coop A1 Andrea L. Sweigart YR 2013 UL http://biorxiv.org/content/early/2013/11/07/000109.abstract AB Mimulus guttatus and M. nasutus are an evolutionary and ecological model sister species pair differentiated by ecology, mating system, and partial reproductive isolation. Despite extensive research on this system, the history of divergence and differentiation in this sister pair is unclear. We present and analyze a novel population genomic data set which shows that M. nasutus “budded” off of a central Californian M. guttatus population within the last 200 to 500 thousand years. In this time, the M. nasutus genome has accrued numerous genomic signatures of the transition to predominant selfing. Despite clear biological differentiation, we document ongoing, bidirectional introgression. We observe a negative relationship between the recombination rate and divergence between M. nasutus and sympatric M. guttatus samples, suggesting that selection acts against M. nasutus ancestry in M. guttatus.