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Effect of the MC 1R gene on sexual dimorphism in melanin‐based colorations
Author(s) -
SanJose Luis M.,
Ducrest AnneLyse,
Ducret Valérie,
Béziers Paul,
Simon Céline,
Wakamatsu Kazumasa,
Roulin Alexandre
Publication year - 2015
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/mec.13193
Subject(s) - sexual dimorphism , biology , melanocortin 1 receptor , nonsynonymous substitution , evolutionary biology , genetics , zoology , sexual selection , plumage , genetic variation , gene , phenotype , genome
Abstract Variants of the melanocortin‐1 receptor ( MC 1R ) gene result in abrupt, naturally selected colour morphs. These genetic variants may differentially affect sexual dimorphism if one morph is naturally selected in the two sexes but another morph is naturally or sexually selected only in one of the two sexes (e.g. to confer camouflage in reproductive females or confer mating advantage in males). Therefore, the balance between natural and sexual selections can differ between MC 1R variants, as suggest studies showing interspecific correlations between sexual dimorphism and the rate of nonsynonymous vs . synonymous amino acid substitutions at the MC 1R . Surprisingly, how MC 1R is related to within‐species sexual dimorphism, and thereby to sex‐specific selection, has not yet been investigated. We tackled this issue in the barn owl ( Tyto alba ), a species showing pronounced variation in the degree of reddish pheomelanin‐based coloration and in the number and size of black feather spots. We found that a valine (V)‐to‐isoleucine (I) substitution at position 126 explains up to 30% of the variation in the three melanin‐based colour traits and in feather melanin content. Interestingly, MC 1R genotypes also differed in the degree of sexual colour dimorphism, with individuals homozygous for the II MC 1R variant being 2 times redder and 2.5 times less sexually dimorphic than homozygous individuals for the VV MC 1R variant. These findings support that MC 1R interacts with the expression of sexual dimorphism and suggest that a gene with major phenotypic effects and weakly influenced by variation in body condition can participate in sex‐specific selection processes.