« Genotypic adaptation to volcanic risk at the dopamine receptor DRD4 locus »
L’exposé sera en français. Venez nombreux l’écouter salle Louis Thaler bâtiment 22 2ième étage, ISEM, Université de Montpellier, à 11h.
suit son résumé
Humans have colonized and adapted to extremely diverse environments, and the genetic basis of some such adaptations, for example to high altitude, is understood. In some cases, local or regional variation in selection pressure could also cause behavioural adaptations. Numerous genes influence behaviour, such as alleles at the dopamine receptor locus D4 (DRD4), which are associated with attitude toward risk in experimental settings. However, selection acting on such genes has not yet been described. We demonstrate genetic differentiation for this gene, but not for five unlinked microsatellite loci, between high- and low risk environments around Mount Merapi, an active volcano in Java, Indonesia. Using a behavioral experiment, we further show that people inhabiting the high risk environment are significantly more risk averse. We provide evidence of a genetic basis for this difference, showing that heterozygotes at the DRD4 locus are more risk averse than either homozygotes. In the high risk environment, allele frequencies are equilibrated, generating a high frequency of heterozygotes. Thus it appears that behavioral overdominance generates negative frequency dependent selection, favoring the rarer allele at this locus. This is the first evidence in humans of adaptation to a marginal habitat for a neurocognitive trait with a genetic basis.