L'introgression de l'ADN mitochondrial chez l'omble de fontaine, Salvelinus fontinalis, dans l'est du Québec: caractérisation, distribution géographique et signification évolutive = Mitochondrial DNA introgression in brook char, Salvelinus fontinalis, from Eastern Quebec : characterization, geographical distribution and evolutionary significance.

• Main Author: Glémet, Hélène Cécile
• Format: Article in Journal/Newspaper
• Language: French
• Published: 1997
• Subjects: ADN mitochondrial; omble de fontaine; Salvelinus fontinalis; espèce; évolution; fertilisation; hybridation; poisson; population; Québec; Arctic
• Online Access: https://espace.inrs.ca/id/eprint/1563/; https://espace.inrs.ca/id/eprint/1563/1/T000233.pdf

A population of brook char (Salvelinus fontinalis) from lac Alain situated in the Portneuf river system of eastem Quebec was discovered to be introgressed with the mitochondrial DNA (mtDNA) of the more northerly occurring Arctic char (S. alpinus). Individuals from this population resembled typièal brook char based on allozyme analysis and several morphological and meristic characteristics. Based on RFLP analysis, all individuals were fixed for the Arctic char mtDNA haplotype, despite the present absence of Arctic char in the watershed. The geographical extent of mtDNA introgression was determined by the genetic assessment of populations from both within the Portneuf river system, as well as from neighboring watersheds. Introgressed populations were restricted to lakes occurring along one branch of the Portneuf river system, otherwise, elsewhere in the watershed. populations were that of geneticaIly pure brook char. AlI populations tested from neighboring drainages were aIso geneticaIly pure brook char. It is probable that a combination of biogeographical conditions coupled with positive selection for mtDNA introgression led to the present-day distribution of introgressed S.fontinalis. The evolutionary importance of mtDNA introgression was investigated by using an experimental approach which involved the assessment of physiological performance of both introgressed and non-introgressed brook char at different levels of biological organization. This approach aIlowed any physiologicaI advantage imparted by the intDNA of an arctic species (via the proteins it encodes), to be identified in introgressed brook char. As a tirst step of this approach, the catalytic efficiency, as weil as the thermal sensitivity of cytochrome C oxidase (CCO), an enzyme partly encoded by mtDNA was determined in red muscle mitochondria DifferentiaI responses in catalytic efficiency and QIO values between char groups were observed for CCO and suggest an influence by the mitochondriaI genome on enzyme structure and function. Based on these ...