Adaptive divergence of ancient gene duplicates in the avian MHC class II beta.

Détails

ID Serval
serval:BIB_58E9592A045F
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
Adaptive divergence of ancient gene duplicates in the avian MHC class II beta.
Périodique
Molecular Biology and Evolution
Auteur(s)
Burri R., Salamin N., Studer R.A., Roulin A., Fumagalli L.
ISSN
1537-1719[electronic], 0737-4038[linking]
Statut éditorial
Publié
Date de publication
2010
Peer-reviewed
Oui
Volume
27
Numéro
10
Pages
2360-2374
Langue
anglais
Résumé
Gene duplication and neofunctionalization are known to be important processes in the evolution of phenotypic complexity. They account for important evolutionary novelties that confer ecological adaptation, such as the major histocompatibility complex (MHC), a multigene family crucial to the vertebrate immune system. In birds, two MHC class II β (MHCIIβ) exon 3 lineages have been recently characterized, and two hypotheses for the evolutionary history of MHCIIβ lineages were proposed. These lineages could have arisen either by 1) an ancient duplication and subsequent divergence of one paralog or by 2) recent parallel duplications followed by functional convergence. Here, we compiled a data set consisting of 63 MHCIIβ exon 3 sequences from six avian orders to distinguish between these hypotheses and to understand the role of selection in the divergent evolution of the two avian MHCIIβ lineages. Based on phylogenetic reconstructions and simulations, we show that a unique duplication event preceding the major avian radiations gave rise to two ancestral MHCIIβ lineages that were each likely lost once later during avian evolution. Maximum likelihood estimation shows that following the ancestral duplication, positive selection drove a radical shift from basic to acidic amino acid composition of a protein domain facing the α-chain in the MHCII α β-heterodimer. Structural analyses of the MHCII α β-heterodimer highlight that three of these residues are potentially involved in direct interactions with the α-chain, suggesting that the shift following duplication may have been accompanied by coevolution of the interacting α- and β-chains. These results provide new insights into the long-term evolutionary relationships among avian MHC genes and open interesting perspectives for comparative and population genomic studies of avian MHC evolution.
Mots-clé
Adaptation, Biological/genetics, Amino Acid Sequence, Animals, Bayes Theorem, Birds/genetics, Computational Biology, Computer Simulation, Evolution, Molecular, Exons/genetics, Genes, Duplicate/genetics, Genes, MHC Class II/genetics, Likelihood Functions, Models, Genetic, Phylogeny, Selection, Genetic, Sequence Alignment
Pubmed
Web of science
Création de la notice
06/05/2010 19:40
Dernière modification de la notice
20/08/2019 15:12
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