Rapid molecular evolution in adaptive genomics

点击翻译按钮获取中文摘要

Understanding the molecular evolution of rapid adaptation in natural populations is critical given the current pace of climate change. 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. As a result of these range expansions, notable increases in hybridization are resulting from more secondary contact between previously isolated species, subspecies, and ecotypes. These distributional changes and interactions will have profound effects on biodiversity and ecological processes. Adaptive evolution under novel conditions can be facilitated by selection acting on standing genetic variation; de novo mutations; and/or introgression. Most genomic surveys of rapid evolution have focused on detecting single nucleotide polymorphisms (SNPs), with a recognition that other structural variants (SVs) and copy number variants (CNVs) may further facilitate adaptive potential. My research program examines genome-wide surveys of natural systems having undergone shifts in their environments to elucidate the relative roles of standing variation, de novo mutation and introgression on rapid evolution on two classes of variable coding sites: SNPs and a class of CNV, specifically gene associated microsatellites. SNPs are commonly surveyed in genomic studies of adaptation; however, genic microsatellites offer significantly different properties that support their role in adaptive evolution, specifically: higher rates of de novo mutation; signatures of selection; and the convergence of allele sizes potentially supporting parallel adaptations. These largely overlooked motifs may be important natural agents that may keep pace with contemporary climate change and range redistribution into novel 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. A comprehensive mapping of functionally adaptive genomic motifs will support the recognition of Designatable Units (DUs) under the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) in supporting "at-risk" listing decisions under the Species-at-Risk Act (SARA). 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, and the current environmental situation where the climate has, and will continue, to change.