Biased gene conversion and GC-content evolution in the coding sequences of reptiles and vertebrates.

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Etat: Public
Version: de l'auteur
ID Serval
serval:BIB_2D00D45E629B
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
Biased gene conversion and GC-content evolution in the coding sequences of reptiles and vertebrates.
Périodique
Genome Biology and Evolution
Auteur(s)
Figuet E., Ballenghien M., Romiguier J., Galtier N.
ISSN
1759-6653 (Electronic)
ISSN-L
1759-6653
Statut éditorial
Publié
Date de publication
2015
Volume
7
Numéro
1
Pages
240-250
Langue
anglais
Résumé
Mammalian and avian genomes are characterized by a substantial spatial heterogeneity of GC-content, which is often interpreted as reflecting the effect of local GC-biased gene conversion (gBGC), a meiotic repair bias that favors G and C over A and T alleles in high-recombining genomic regions. Surprisingly, the first fully sequenced nonavian sauropsid (i.e., reptile), the green anole Anolis carolinensis, revealed a highly homogeneous genomic GC-content landscape, suggesting the possibility that gBGC might not be at work in this lineage. Here, we analyze GC-content evolution at third-codon positions (GC3) in 44 vertebrates species, including eight newly sequenced transcriptomes, with a specific focus on nonavian sauropsids. We report that reptiles, including the green anole, have a genome-wide distribution of GC3 similar to that of mammals and birds, and we infer a strong GC3-heterogeneity to be already present in the tetrapod ancestor. We further show that the dynamic of coding sequence GC-content is largely governed by karyotypic features in vertebrates, notably in the green anole, in agreement with the gBGC hypothesis. The discrepancy between third-codon positions and noncoding DNA regarding GC-content dynamics in the green anole could not be explained by the activity of transposable elements or selection on codon usage. This analysis highlights the unique value of third-codon positions as an insertion/deletion-free marker of nucleotide substitution biases that ultimately affect the evolution of proteins.
Mots-clé
third-codon positions, phylogeny, karyotype
Pubmed
Web of science
Open Access
Oui
Création de la notice
26/03/2015 11:43
Dernière modification de la notice
20/08/2019 14:12
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