Genetic variation between individuals is ubiquitous across the tree of life, and a requirement for both adaptive and non-adaptive evolutionary change. Processes that affect the genetic variation within species can affect their evolutionary potential. Geographic differences in the strength and direction of natural selection lead to local adaptation of populations and the maintenance of genetic variation at a species level, even when variation would have otherwise have been lost. Although this process has potentially dramatic consequences for adaptation by natural selection, its relative importance in shaping the evolutionary fate of species is unknown. Rocky Mountain columbine grows at high elevations in the Southern Rockies, a region characterized by strong environmental gradients such as summer precipitation (i.e. monsoonal rain in the south and almost none in the north). The proposed research will identify variable genetic regions through whole-genome sequencing of hundreds of individuals across the species? distribution, and patterns of genetic variation will be used to identify those regions that are experiencing geographically variable natural selection. Greenhouse experiments will test whether precipitation could differentially affect fitness of variants for one trait that shows geographic variation, flower color.
The proposed research will provide important insight into how environmental differences across a species range affect genetic variation at the whole-genome level. This relationship is critical to understanding how biological diversity originates and is maintained through time in the face of a variable and changing environment. In light of rapid global climate change, such an understanding takes on particular significance. Training of students will result from this work.
