Centromere-associated meiotic drive and female fitness variation in Mimulus

This is the peer reviewed version of the following article: Fishman, L. and Kelly, J. K. (2015), Centromere‐associated meiotic drive and female fitness variation in Mimulus. Evolution, 69: 1208-1218. doi:10.1111/evo.12661, which has been published in final form at http://doi.org/10.1111/evo.12661. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.Female meiotic drive, in which chromosomal variants preferentially segregate to the egg pole during asymmetric female meiosis, is a theoretically pervasive but still mysterious form of selfish evolution. Like other selfish genetic elements, driving chromosomes may be maintained as balanced polymorphisms by pleiotropic or linked fitness costs. A centromere-associated driver (D) with a ~58:42 female-specific transmission advantage occurs at intermediate frequency (32–40%) in the Iron Mountain population of the yellow monkeyflower, Mimulus guttatus. Previously determined male fertility costs are sufficient to prevent the fixation of D, but predict a higher equilibrium frequency. To better understand the dynamics and effects of D, we developed a new population genetic model and measured genotype-specific lifetime female fitness in the wild. In three of four years, and across all years, D imposed significant recessive seedset costs, most likely due to hitchhiking by deleterious mutations. With both male and female costs as measured, and 58:42 drive, our model predicts an equilibrium frequency of D (38%) very close to the observed value. Thus, D represents a rare selfish genetic element whose local population genetic dynamics have been fully parameterized, and the observation of equilibrium sets the stage for investigations of coevolution with suppressors