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Diversifying selection on MHC class I in the house sparrow ( Passer domesticus )
Author(s) -
LOISEAU CLAIRE,
RICHARD MURIELLE,
GARNIER STÉPHANE,
CHASTEL OLIVIER,
JULLIARD ROMAIN,
ZOOROB RIMA,
SORCI GABRIELE
Publication year - 2009
Publication title -
molecular ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.619
H-Index - 225
eISSN - 1365-294X
pISSN - 0962-1083
DOI - 10.1111/j.1365-294x.2009.04105.x
Subject(s) - biology , major histocompatibility complex , balancing selection , evolutionary biology , genetics , population , selection (genetic algorithm) , local adaptation , sparrow , mhc class i , microsatellite , allele , gene , ecology , demography , artificial intelligence , sociology , computer science
Genes of the major histocompatibility complex (MHC) are the most polymorphic loci known in vertebrates. Two main hypotheses have been put forward to explain the maintenance of MHC diversity: pathogen‐mediated selection and MHC‐based mate choice. Host–parasite interactions can maintain MHC diversity via frequency‐dependent selection, heterozygote advantage, and diversifying selection (spatially and/or temporally heterogeneous selection). In this study, we wished to investigate the nature of selection acting on the MHC class I across spatially structured populations of house sparrows ( Passer domesticus ) in France. To infer the nature of the selection, we compared patterns of population differentiation based on two types of molecular markers: MHC class I and microsatellites. This allowed us to test whether the observed differentiation at MHC genes merely reflects demographic and/or stochastic processes. At the global scale, diversifying selection seems to be the main factor maintaining MHC diversity in the house sparrow. We found that (i) overall population differentiation at MHC was stronger than for microsatellites, (ii) MHC marker showed significant isolation by distance. In addition, the slope of the regression of F ST on geographical distance was significantly steeper for MHC than for microsatellites due to a stronger pairwise differentiation between populations located at large geographical distances. These results are in agreement with the hypothesis that spatially heterogeneous selective pressures maintain different MHC alleles at local scales, possibly resulting in local adaptation.