Genetic variation for shell traits in a direct-developing marine snail involved in a putative sympatric ecological speciation process

摘要: Populations of the marine gastropod Littorina saxatilis from exposed rocky shores NW Spain provide one few putative cases sympatric ecological speciation. Two ecotypes with large differences in shell morphology and strong assortative mating are living at different vertical levels shore separated by a meters. It has been hypothesized that size is main determinant for reproductive isolation observed between ecotypes, several shape traits subject to divergent natural selection responsible adaptation each ecotype its respective habitat. Using embryos extracted wild females we obtain estimates genetic variation compare them those neutral molecular markers. Estimates heritability significantly larger found upper than lower shore, concordance similar result heterozygosity The differentiation traits, contrasting smaller close populations same ecotype, supports implication adaptation.