The process of speciation begins with genomically-localised barriers to gene exchange associated with loci for local adaptation, intrinsic incompatibility or assortative mating. The barrier then spreads until reproductive isolation influences the whole genome. The population genomics approach can be used to identify regions of reduced gene flow by detecting loci with greater differentiation than expected from the average across many loci. Recently, this approach has been used in several systems. I review these studies, concentrating on the robustness of the approach and the methods available to go beyond the simple identification of differentiated markers. Population genomics has already contributed significantly to understanding the balance between gene flow and selection during the evolution of reproductive isolation and has great future potential both in genome species and in non-model organisms.
KeywordsFST Genome scan Reproductive isolation Local adaptation
I am very grateful to Jacob Hoglund and Gernot Segelbacher for organising, and inviting me to attend, the very stimulating workshop from which these proceedings are derived. The workshop was funded by the European Science Foundation. Discussions with Juan Galindo about population genomics approaches have been important in the development of this paper. My work on Littorina is in collaboration with John Grahame and has been funded by the BBSRC.
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