Population and landscape genomics of rapidly evolving gene motifs and introgressive hybridization and their role in adaptation

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We are currently in a period of global warming that is having dramatic effects on species distributions worldwide. Geographic expansions of northern range boundaries are occurring for many species, while the range margins at their southern peripheral distribution are impacted by less suitable habitat and increased isolation resulting from anthropogenic activities and increased biotic stress. Furthermore, notable increases in hybridization are resulting from more secondary contact between previously isolated species. These distributional changes and species interactions will have profound effects on biodiversity and ecological processes. Understanding how standing genetic variation and genomic elements operating at higher rates of change, and hybridization all contribute to adaptability will be important to determining a wildlife population’s "response capacity" or "adaptive potential". Targeting gene motifs that may rapidly change to key up with the rate of environmental change is an important first step and coding trinucleotide repeats, most commonly associated with human genetic diseases, may in fact be important natural agents under selection that can keep pace with the contemporary climate change and range redistribution into novel environments. The advancement of next-generation sequencing platforms applied to characterizing these repeats in comprehensive studies of flying squirrels (Glaucomys) and deer mice (Peromyscus) will contribute to our understanding of the genomics of adaptation associated with these variable coding repeat motifs. Furthermore, these species have undergone very recent hybridization, thereby allowing an assessment of the transfer of genes between the southern and northern species within each genera. A study on domesticated mink compared to wild populations, as well as areas where escape farmed mink and wild mink interbreed, will further assess the potential dynamic nature of these repeat motifs having experienced significant shifts in selection pressures in captivity, with subsequent escape and re-entry into natural surroundings and interbreeding with natural local populations. A molecular genetic study of these “model” species will provide important insight into the role rapidly evolving genomic elements and the capacity of hybridization have on facilitating a populations ability to adapt to changing local environments. This research is important for government researchers, policy makers as well as industry to more fully understand the mitigation that will be required with significant range re-distribution of wildlife species and species-at-risk in the future, and not just the current "snapshot" of the environmental landscape. This will yield more effective management strategies to maintain the adaptive potential of natural populations given the increasing development of natural resource industries in Canada.