Molecular evolution of Drosophila Sex-lethal and related sex determining genes.

Détails

ID Serval
serval:BIB_F0A876F5E91F
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Molecular evolution of Drosophila Sex-lethal and related sex determining genes.
Périodique
BMC Evolutionary Biology
Auteur(s)
Mullon C., Pomiankowski A., Reuter M.
ISSN
1471-2148 (Electronic)
ISSN-L
1471-2148
Statut éditorial
Publié
Date de publication
2012
Peer-reviewed
Oui
Volume
12
Pages
5
Langue
anglais
Résumé
BACKGROUND: Sex determining mechanisms are evolutionarily labile and related species often use different primary signals and gene regulatory networks. This is well illustrated by the sex determining cascade of Drosophila fruitflies, which have recruited Sex-lethal as the master switch and cellular memory of sexual identity, a role performed in other insects by the gene transformer. Here we investigate the evolutionary change in the coding sequences of sex determining genes associated with the recruitment of Sex-lethal. We analyze sequences of Sex-lethal itself, its Drosophila paralogue sister-or-Sex-lethal and downstream targets transformer and doublesex.
RESULTS: We find that the recruitment of sister-or-Sex-lethal was associated with a number of adaptive amino acid substitutions, followed by a tightening of purifying selection within the Drosophila clade. Sequences of the paralogue sister-or-Sex-lethal, in contrast, show a signature of rampant positive selection and relaxation of purifying selection. The recruitment of Sex-lethal as top regulator and memory gene is associated with a significant release from purifying selection in transformer throughout the Drosophila clade. In addition, doublesex shows a signature of positive selection and relaxation of purifying selection in the Drosophila clade. A similar pattern is seen in sequences from the sister Tephritidae clade.
CONCLUSIONS: The pattern of molecular evolution we observe for Sex-lethal and its paralogue sister-or-Sex-lethal is not characteristic of a duplication followed by neo-functionalization. Rather, evidence suggests a sub-functionalization scenario achieved through the evolution of sophisticated splicing. As expected, we find that transformer evolves under relaxed purifying selection after the recruitment of Sex-lethal in Drosophila. Finally, the observation of doublesex adaptation in both Drosophila and Tephritidae suggests that these changes are due to ongoing adaptation of downstream sex-specific regulation, rather than being associated the recruitment of Sex-lethal and the resulting change in the topology of the sex determining cascade.
Mots-clé
Animals, Drosophila Proteins/genetics, Drosophila melanogaster/genetics, Drosophila melanogaster/metabolism, Evolution, Molecular, Female, Insect Proteins/genetics, Male, Muscidae/classification, Muscidae/genetics, RNA-Binding Proteins/genetics, Sex Determination Processes, Tephritidae/classification, Tephritidae/genetics
Pubmed
Web of science
Open Access
Oui
Création de la notice
24/01/2013 16:04
Dernière modification de la notice
20/08/2019 17:18
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