Titre :

Sheltering of deleterious mutations explains the stepwise extension of recombination suppression on sex chromosomes and other supergenes

Auteur(s) :

Jay, Paul [Auteur]
Ecologie Systématique et Evolution [ESE]
Tezenas, Emilie [Auteur]
Ecologie Systématique et Evolution [ESE]
Mathématiques Appliquées Paris 5 [MAP5 - UMR 8145]
Évolution, Écologie et Paléontologie (Evo-Eco-Paleo) - UMR 8198 [Evo-Eco-Paléo (EEP)]
Véber, Amandine [Auteur]
Mathématiques Appliquées Paris 5 [MAP5 - UMR 8145]
Giraud, Tatiana [Auteur]
Ecologie Systématique et Evolution [ESE]

Titre de la revue :

PLoS Biology

Pagination :

e3001698

Éditeur :

Public Library of Science

Date de publication :

2022-07-19

ISSN :

1544-9173

Discipline(s) HAL :

Sciences du Vivant [q-bio]/Génétique/Génétique des populations [q-bio.PE]
Sciences du Vivant [q-bio]/Bio-Informatique, Biologie Systémique [q-bio.QM]

Résumé en anglais : [en]

Many organisms have sex chromosomes with large nonrecombining regions that have expanded stepwise, generating "evolutionary strata" of differentiation. The reasons for this remain poorly understood, but the principal ...
Lire la suite >Many organisms have sex chromosomes with large nonrecombining regions that have expanded stepwise, generating "evolutionary strata" of differentiation. The reasons for this remain poorly understood, but the principal hypotheses proposed to date are based on antagonistic selection due to differences between sexes. However, it has proved difficult to obtain empirical evidence of a role for sexually antagonistic selection in extending recombination suppression, and antagonistic selection has been shown to be unlikely to account for the evolutionary strata observed on fungal mating-type chromosomes. We show here, by mathematical modeling and stochastic simulation, that recombination suppression on sex chromosomes and around supergenes can expand under a wide range of parameter values simply because it shelters recessive deleterious mutations, which are ubiquitous in genomes. Permanently heterozygous alleles, such as the male-determining allele in XY systems, protect linked chromosomal inversions against the expression of their recessive mutation load, leading to the successive accumulation of inversions around these alleles without antagonistic selection. Similar results were obtained with models assuming recombination-suppressing mechanisms other than chromosomal inversions and for supergenes other than sex chromosomes, including those without XY-like asymmetry, such as fungal mating-type chromosomes. However, inversions capturing a permanently heterozygous allele were found to be less likely to spread when the mutation load segregating in populations was lower (e.g., under large effective population sizes or low mutation rates). This may explain why sex chromosomes remain homomorphic in some organisms but are highly divergent in others. Here, we model a simple and testable hypothesis explaining the stepwise extensions of recombination suppression on sex chromosomes, mating-type chromosomes, and supergenes in general.Lire moins >

Langue :

Anglais

Vulgarisation :

Non

Projet Européen :

Testing new hypotheses on the evolution of sex-related chromosomes

Collections :

• Évolution, Écologie et Paléontologie (Evo Eco Paleo) - UMR 8198

Source :

Harvested from HAL