title: Linkage to the mating-type locus across the genus Microbotryum: insights into nonrecombining chromosomes.
abstract: Parallels have been drawn between the evolution of nonrecombining regions in fungal mating-type chromosomes and animal and plant sex chromosomes, particularly regarding the stages of recombination cessation forming evolutionary strata of allelic divergence. Currently, evidence and explanations for recombination cessation in fungi are sparse, and the presence of evolutionary strata has been examined in a minimal number of fungal taxa. Here, the basidiomycete genus Microbotryum was used to determine the history of recombination cessation for loci on the mating-type chromosomes. Ancestry of linkage with mating type for 13 loci was assessed across 20 species by a phylogenetic method. No locus was found to exhibit trans-specific polymorphism for alternate alleles as old as the mating pheromone receptor, indicating that ages of linkage to mating type varied among the loci. The ordering of loci in the ancestry of linkage to mating type does not agree with their previously proposed assignments to evolutionary strata. This study suggests that processes capable of influencing divergence between alternate alleles may act at loci in the nonrecombining regions (e.g., gene conversion) and encourages further work to dissect the evolutionary processes acting upon genomic regions that determine mating compatibility.
authors.affiliation: Department of Biology, Amherst College, Amherst, Massachusetts 01002, USA. mhood@amherst.edu
authors.forename: Elsa
authors.initials: E
authors.lastname: Petit
authors.forename: Tatiana
authors.initials: T
authors.lastname: Giraud
authors.forename: Damien M
authors.initials: DM
authors.lastname: de Vienne
authors.forename: Marco A
authors.initials: MA
authors.lastname: Coelho
authors.forename: Gabriela
authors.initials: G
authors.lastname: Aguileta
authors.forename: Joëlle
authors.initials: J
authors.lastname: Amselem
authors.forename: Jonathan
authors.initials: J
authors.lastname: Kreplak
authors.forename: Julie
authors.initials: J
authors.lastname: Poulain
authors.forename: Frédérick
authors.initials: F
authors.lastname: Gavory
authors.forename: Patrick
authors.initials: P
authors.lastname: Wincker
authors.forename: Sarah K
authors.initials: SK
authors.lastname: Young
authors.forename: Christina
authors.initials: C
authors.lastname: Cuomo
authors.forename: Michael H
authors.initials: MH
authors.lastname: Perlin
authors.forename: Michael E
authors.initials: ME
authors.lastname: Hood
mesh_terms: D000483:Alleles; D001487:Basidiomycota / Q000235:genetics* / Q000502:physiology; D018076:DNA, Complementary / Q000032:analysis; D004271:DNA, Fungal / Q000032:analysis; D019143:Evolution, Molecular; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D049770:Genes, Mating Type, Fungal; D008040:Genetic Linkage; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D043563:Receptors, Pheromone / Q000235:genetics* / Q000378:metabolism; D011995:Recombination, Genetic; D017422:Sequence Analysis, DNA; D013045:Species Specificity
chemical_list: D018076:DNA, Complementary; D004271:DNA, Fungal; D005656:Fungal Proteins; D043563:Receptors, Pheromone