title: Centromere-associated meiotic drive and female fitness variation in Mimulus.
abstract: 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.
authors: Division of Biological Sciences, University of Montana, Montana, Missoula, 59812. lila.fishman@mso.umt.edu.
authors: Lila
authors: L
authors: Fishman
authors: Department of Ecology and Evolutionary Biology, University of Kansas, Kansas, Lawrence, 66045.
authors: John K
authors: JK
authors: Kelly
mesh_terms: D002503:Centromere / Q000235:genetics*; D023902:Chromosome Pairing; D032461:Chromosomes, Plant / Q000235:genetics; D019143:Evolution, Molecular; D005808:Genes, Recessive; D056084:Genetic Fitness; D014644:Genetic Variation; D015810:Linkage Disequilibrium; D008540:Meiosis; D032241:Mimulus / Q000235:genetics*; D008957:Models, Genetic; D051479:Plant Infertility / Q000235:genetics; D012091:Repetitive Sequences, Nucleic Acid
keywords: Balancing selection; centromere; genetic conflict; polymorphism; seedset; selfish genetic element; standing variation