Lack of evidence for selection favouring MHC haplotypes that combine high functional diversity.

Détails

ID Serval
serval:BIB_E25CB8C311AC
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Lack of evidence for selection favouring MHC haplotypes that combine high functional diversity.
Périodique
Heredity
Auteur(s)
Gaigher A., Roulin A., Gharib W.H., Taberlet P., Burri R., Fumagalli L.
ISSN
1365-2540 (Electronic)
ISSN-L
0018-067X
Statut éditorial
Publié
Date de publication
05/2018
Peer-reviewed
Oui
Volume
120
Numéro
5
Pages
396-406
Langue
anglais
Notes
Publication types: Journal Article ; Research Support, Non-U.S. Gov't
Publication Status: ppublish
Résumé
High rates of gene duplication and the highest levels of functional allelic diversity in vertebrate genomes are the main hallmarks of the major histocompatibility complex (MHC), a multigene family with a primordial role in pathogen recognition. The usual tight linkage among MHC gene duplicates may provide an opportunity for the evolution of haplotypes that associate functionally divergent alleles and thus grant the transmission of optimal levels of diversity to coming generations. Even though such associations may be a crucial component of disease resistance, this hypothesis has been given little attention in wild populations. Here, we leveraged pedigree data from a barn owl (Tyto alba) population to characterize MHC haplotype structure across two MHC class I (MHC-I) and two MHC class IIB (MHC-IIB) duplicates, in order to test the hypothesis that haplotypes' genetic diversity is higher than expected from randomly associated alleles. After showing that MHC loci are tightly linked within classes, we found limited evidence for shifts towards MHC haplotypes combining high diversity. Neither amino acid nor functional within-haplotype diversity were significantly higher than in random sets of haplotypes, regardless of MHC class. Our results therefore provide no evidence for selection towards high-diversity MHC haplotypes in barn owls. Rather, high rates of concerted evolution may constrain the evolution of high-diversity haplotypes at MHC-I, while, in contrast, for MHC-IIB, fixed differences among loci may provide barn owls with already optimized functional diversity. This suggests that at the MHC-I and MHC-IIB respectively, different evolutionary dynamics may govern the evolution of within-haplotype diversity.
Mots-clé
Alleles, Amino Acid Sequence, Evolution, Molecular, Genetic Linkage, Haplotypes, Major Histocompatibility Complex/genetics, Sequence Alignment
Pubmed
Web of science
Open Access
Oui
Création de la notice
15/12/2017 12:12
Dernière modification de la notice
19/06/2019 6:11
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