W240 The ecological genomics of adaptation and speciation in whitefish

Date: Saturday, January 14, 2012
Time: 8:20 AM
Room: Sunrise
Louis Bernatchez , Université Laval, Québec, QC, Canada
In contrast to the large amount of ecological information supporting the role of natural selection as a main cause of population divergence and speciation, understanding of the genomic basis underlying those processes is in its infancy. In this talk, I will present our long-term research program on the ecological genomics of sympatric forms of lake whitefish (Coregonus spp.) as an example of how applying a combination of phenotypic, ecological and genomics approaches under the conceptual framework of the theory of adaptive radiation has yielded insight towards this goal. First, combining information obtained both from a comparison of phenotypic and transcriptomic differentiation among multiple species pairs allowed identifying phenotypic traits most likely to be associated with adaptive divergence. Second, the combined, integrated use of linkage, phenotypic, and gene expression mapping provided an efficient means to elucidate the genetic architecture of these adaptive traits differentiating dwarf and normal whitefish. Third, integrating pQTL and eQTL mapping with population genomics of multiple sympatric pairs allow to test for parallelism in genomic regions resisting the homogenizing influence of gene flow and therefore likely to be under selection causing hitchhiking divergence.  Finally, comparative analysis of genome-wide transcription patterns identified both extrinsic and intrinsic mechanisms of reproductive isolation and provided insight into their genetic basis. Given increasing access to high throughput genomic tools, it is clear that non-model species studied in their ecological context, such as whitefish species pairs, will play an increasingly important role in generalising knowledge pertaining to the process of ecological speciation.