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Microsatellite length variation in candidate genes correlates with habitat in the gilthead sea bream S parus aurata
Author(s) -
Chaoui Lamya,
Gagnaire PierreAlexandre,
Guinand Bruno,
Quignard JeanPierre,
Tsigenopoulos Costas,
Kara M. Hichem,
Bonhomme François
Publication year - 2012
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.12062
Subject(s) - biology , local adaptation , habitat , candidate gene , genotype , allele , microsatellite , ecology , gene , genetics , gene flow , genetic variation , evolutionary biology , population , demography , sociology
The genetic basis and evolutionary implications of local adaptation in high gene flow marine organisms are still poorly understood. In several M editerranean fish species, alternative migration patterns exist between individuals entering coastal lagoons that offer favourable conditions for growth and those staying in the sea where environmental conditions are less subject to rapid and stressful change. Whether these coexisting strategies are phenotypically plastic or include a role for local adaptation through differential survival needs to be determined. Here, we explore the genetic basis of alternate habitat use in western M editerranean populations of the gilthead sea bream ( S parus aurata ). Samples from lagoonal and open‐sea habitats were typed for three candidate gene microsatellite loci, seven anonymous microsatellites and 44 amplified fragment length polymorphism markers to test for genotype–environment associations. While anonymous markers globally indicated high levels of gene flow across geographic locations and habitats, non‐neutral differentiation patterns correlated with habitat type were found at two candidate microsatellite loci located in the promoter region of the growth hormone and prolactin genes. Further analysis of these two genes revealed that a mechanism based on habitat choice alone could not explain the distribution of genotype frequencies at a regional scale, thus implying a role for differential survival between habitats. We also found an association between allele size and habitat type, which, in the light of previous studies, suggests that polymorphisms in the proximal promoter region could influence gene expression by modulating transcription factor binding, thus providing a potential explanatory link between genotype and growth phenotype in nature.