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How did the guppy Y chromosome evolve?

Published version
Peer-reviewed

Type

Article

Change log

Authors

Charlesworth, Deborah  ORCID logo  https://orcid.org/0000-0002-3939-9122
Bergero, Roberta 
Gardner, Jim 

Abstract

The sex chromosome pairs of many species do not undergo genetic recombination, unlike the autosomes. It has been proposed that the suppressed recombination results from natural selection favouring close linkage between sex-determining genes and mutations on this chromosome with advantages in one sex, but disadvantages in the other (these are called sexually antagonistic mutations). No example of such selection leading to suppressed recombination has been described, but populations of the guppy display sexually antagonistic mutations (affecting male coloration), and would be expected to evolve suppressed recombination. In extant close relatives of the guppy, the Y chromosomes have suppressed recombination, and have lost all the genes present on the X (this is called genetic degeneration). However, the guppy Y occasionally recombines with its X, despite carrying sexually antagonistic mutations. We describe evidence that a new Y evolved recently in the guppy, from an X chromosome like that in these relatives, replacing the old, degenerated Y, and explaining why the guppy pair still recombine. The male coloration factors probably arose after the new Y evolved, and have already evolved expression that is confined to males, a different way to avoid the conflict between the sexes.

Description

Keywords

Animals, Evolution, Molecular, Fish Proteins, Male, Poecilia, Recombination, Genetic, Selection, Genetic, Skin Pigmentation, X Chromosome, Y Chromosome

Journal Title

PLoS Genet

Conference Name

Journal ISSN

1553-7390
1553-7404

Volume Title

17

Publisher

Public Library of Science (PLoS)
Sponsorship
European Research Council (695225)