EVOLUTIONARY PROCESSES IN RECENTLY EXPANDED COYOTE (CANIS LATRANS) POPULATIONS: A GENETIC INVESTIGATION OF SUBDIVISION, SELECTION, AND ADMIXTURE EVENTS

Abstract

Coyotes (Canis latrans), a North American evolved canid, were historically limited to the western half of the continent but have recently undergone a spectacular range expansion. Though range expansions are ubiquitous in nature, with well-described theoretical expectations for reduced diversity, selection for dispersal-related traits, and gene flow with established populations, comparatively few empirical studies have demonstrated these evolutionary processes at the genetic level. Using various molecular approaches, I investigate these processes across two populations of recently expanded coyotes in eastern North America. In chapter one, I demonstrate that population subdivisions correspond to the two known eastern expansion fronts, with an emerging mid-Atlantic contact zone between these two populations. In chapter two, I show that genome-wide diversity is relatively high in both recently expanded populations, which contrasts with the theoretical expectations for populations to bottleneck during range expansion. Further, I identify three genes with known functions in dispersal-related traits that may have been under selection during range expansion in both populations. In chapters three and four, I describe recent and on-going admixture between coyotes and closely related red wolves (C. rufus) on a genome-wide scale. In particular, I characterize a previously unknown admixture zone along the American Gulf Coast, where hybridization among red wolves and encroaching coyotes likely occurred prior to the 1980s, and genetic admixtures still persist today. Overall, these studies highlight how recent advances in genomic sequencing techniques allow complex evolutionary questions to be addressed in wild populations.