Local adaptation in the presence of gene flow in Patagonian and Antarctic Nacella limpets: a multimarker genetic and physiological approach

Abstract

The understanding of how speciation works in the ocean has always challenged marine biologists because the marine realm is characterized by the absence of strict barriers to gene flow over large geographical scales. The impact of natural selection as a source of speciation in the marine system has also been considered to be low because of the very high gene flow overriding the effects of locally varying selective pressures. In a top-down approach I analyzed large-scale impacts of emerging geographical barriers and small-scale influences of biogeographic patterning and local adaptations on the evolutionary history of Antarctic and South American Nacella limpets. A large set of genetic and physiological, neutral and selected markers was applied. The results show that natural selection and local adaptation are much more important drivers of marine speciation than previously believed. The application of genetic markers under selection revealed how natural selection is capable to maintain adaptive divergence in parts of a genome to ensure adaptability to environmental constraints even in high gene flow environments.