Research


Adaptation

asymmetry_completeOur research focuses on the process and outcomes of selection in fishes, testing hypotheses about population persistence and the genetic basis of adaptation in response to environmental change. We study the genetic basis of adaptive behaviours, morphology, physiology and plasticity, examining the imprint of selection on genomes during population divergence and speciation (Rogers and Bernatchez; Rogers and Bernatchez 2007; Renaut et al. 2011; Rogers et al. 2012, Rogers et al. 2013, McEwen et al. 2013). 

Figure: A. Stickleback plate morphotypes, showing a typical low-plated fish (top), partially-plated fish (middle), and fully-plated fish (bottom). The first ten plates are numbered on the fully-plated fish; note that some fish as shown are missing some combination of their first two plates; for instance, the plate to first appear on the low-plated fish is plate 3. B. Asymmetry phenotypes, showing the left (top) and right (bottom) sides of a single fully-plated fish. This fish symmetrically has retained most of its plates and its keel, but is symmetrically missing plate 2, and is asymmetrically missing plate 10 from its left side and plate 15 from its right. Total plate count asymmetry would equal 0 for this fish, as the total number of plates on each side of the fish is the same. The total positional asymmetry of this fish would be 2, as asymmetry is noted at two myomere positions. Note that for this fish plate 7 abuts the ascending process on both sides of the fish; there is no relational asymmetry shown in this figure. Morris and Rogers, in revision

Speciation

MEC_04574_whitefishcover

Understanding the remarkable fits between organisms and their environment is a central objective of our research. Dobzhansky (1951) believed that the genotype of a species is an integrated system adapted to the ecological niche in which a species lives.  Such adaptive divergence is predicted to reduce gene flow and result in the formation of reproductive isolation at genes underlying adaptive phenotypes between populations. We compare genomic patterns of diversity between diverging populations to identify and differentiate patterns of polymorphism among populations that do not conform to expectations of neutral demographic models, and how these genomic regions may contribute to adaptation and speciation in postglacial fishes. (Image: Hybrid F1 Lake Whitefish)


Molecular Ecology and Conservation

One of our main research interests is understanding the relative influences of historic and ecological processes that have shaped the present distribution and life histories of species. Historically contingent genetic diversity refers to locally specific selection pressures and stochastic effects that may have influenced isolated assemblages in the past. The role of historical contingency in Canada, due in large part to isolation of species in glacial refugia during the last ice age, has been shown to have a significant role in the evolution of speciation and biodiversity, especially in postglacial populations of fishes. These processes have important conservation implications with respect to taxonomy and the preservation of biodiversity 

(Image: Distribution of five glacial races of lake whitefish in Canada in relation to historic ice age refugia, Mee et al. 2015)