The process of speciation is central to biology because it is responsible for the diversity of life. However, progress in finding general mechanisms for species formation has been slow. One potential solution is ecological speciation, in which adaptation to alternate environments generates reproductive isolation between populations.
Our project will test three key predictions of ecological speciation with stickleback fish from British Columbia, Canada. First, can adaptation to alternate environments generate reproductive isolation? This might occur because their mating systems have diverged, or because hybrids fall between ecological niches. In particular, we will focus on detecting assortative mating between geographically isolated stickleback fish that have adapted to different niches.
Second, are traits that differ between populations under divergent selection? If so, these traits can contribute to reproductive isolation by reducing hybrid fitness: hybrids will be poorly adapted for either parental habitat. We focus on sticklebacks from lakes where two alternately adapted species co-exist (the limnetic-benthic species pairs), and determine whether there is predator-mediated divergent selection acting on the quantitative trait loci responsible for two anti-predator traits. Both experiments will be conducted with Dolph Schluter at the University of British Columbia, Canada.
We will then explore whether divergent selection on these anti-predator traits has been responsible for reducing hybrid fitness in the species pair lakes. This selection will reduce gene flow around each locus, and this should be detectable at the DNA level. As this requires the application of coalescent models of selection and gene flow, I will work with Thomas Lenormand at CEFE in Montpellier, France.
This study will allow me to gain experience with two leading researchers in their respective fields, and will build collaboration between UBC and CEFE in the study of ecological speciation.
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