Centromere-associated Meiotic Drive and Female Fitness Variation in Mimulus

Evolution. 2015 May;69(5):1208-18. doi: 10.1111/evo.12661. Epub 2015 May 8.

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.

Keywords: Balancing selection; centromere; genetic conflict; polymorphism; seedset; selfish genetic element; standing variation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Centromere / genetics*
  • Chromosome Pairing
  • Chromosomes, Plant / genetics
  • Evolution, Molecular
  • Genes, Recessive
  • Genetic Fitness*
  • Genetic Variation*
  • Linkage Disequilibrium
  • Meiosis*
  • Mimulus / genetics*
  • Models, Genetic*
  • Plant Infertility / genetics
  • Repetitive Sequences, Nucleic Acid

Associated data

  • Dryad/10.5061/dryad.DJ6P6