Différenciation génétique et sélection chez le cerf de Virginie (Odocoileus virginianus) introduit sur l'île d'Anticosti
|Advisor:||Bernatchez, Louis; Côté, Steeve D.|
|Abstract:||The introduction of a species is often associated with a loss of genetic variability, referred as the founder effect. Different selection pressures in the colonized environment may also accelerate the genetic divergence of two populations. In 1896, ca. 220 white-tailed deer (Odocoileus virginianus) captured on the southern shore of the St. Lawrence River were introduced on Anticosti Island (Québec, Canada) to develop sport hunting. The absence of predator allowed the population to quickly reached high densities (>20 deer/km2) that affected forest composition because of browsing intensity. Deer body size decreased by half compared to the source population because of their poor-quality diet. Our objectives were to characterize the impacts of the founder effect and selection on the diversity and genetic structure of the deer population on Anticosti Island. We compared the genetic variability of this population to one of the strain populations (Montmagny-L’Islet region) with high throughput sequencing techniques (GBS). The results show a small, albeit significant genetic differentiation, between the source population and Anticosti Island relative to the extent of genetic differentiation between the north and south shores of the St. Lawrence. We found a lack of structuration within the island meaning that the genetic drift did not have a significant magnitude during the colonization of the whole island. The high genetic diversity of the Anticosti deer population and its low differentiation from the mainland suggests a weak founder effect. The large number of introduced individuals and the rapid population growth of the population have undoubtedly helped to reduce genetic drift and explain the maintenance of a great genetic diversity. Loci under putative selection were assigned to the differentiated phenotypic traits supporting an adaptive divergence of the island population.|
|Document Type:||Mémoire de maîtrise|
|Open Access Date:||17 May 2019|
|Collection:||Thèses et mémoires|
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