title: Mate choice among yeast gametes can purge deleterious mutations.
abstract: Meiosis in Saccharomyces yeast produces four haploid gametes that usually fuse with each other, an extreme form of self-fertilization among the products of a single meiosis known as automixis. The gametes signal to each other with sex pheromone. Better-quality gametes produce stronger signals and are preferred as mates. We suggest that the function of this signalling system is to enable mate choice among the four gametes from a single meiosis and so to promote the clearance of deleterious mutations. To support this claim, we construct a mathematical model that shows that signalling during automixis (i) improves the long-term fitness of a yeast colony and (ii) lowers its mutational load. We also show that the benefit to signalling is greater with larger numbers of segregating mutations.
authors.affiliation: CoMPLEX, University College London, Gower St., London, UK. s.tazzyman@ucl.ac.uk
authors.forename: S J
authors.initials: SJ
authors.lastname: Tazzyman
authors.forename: R M
authors.initials: RM
authors.lastname: Seymour
authors.forename: A
authors.initials: A
authors.lastname: Pomiankowski
authors.forename: D
authors.initials: D
authors.lastname: Greig
mesh_terms: D056426:Genetic Loci / Q000235:genetics; D005854:Germ Cells; D008954:Models, Biological; D009154:Mutation; D010675:Pheromones / Q000235:genetics; D012100:Reproduction, Asexual / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000502:physiology*
chemical_list: D010675:Pheromones