Plant, Animal & Microbe Genomes X Conference

January 12-16, 2002
Town & Country Convention Center
San Diego, CA

Workshop: Aquaculture
            

COMPARATIVE MAPPING OF QTL IN SALMONID FISHES

¹ Department of Zoology, University of Guelph, Guelph, Ontario, N1G 2W1, Canada

We are using comparative mapping to investigate the genetic architecture of fitness traits in Arctic charr (Salvelinus alpinus), Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss). Towards this end, we are constructing genetic linkage maps in collaboration with other groups in North America, Europe (SALMAP) and Japan. The maps are then used to locate quantitative trait loci (QTL) for upper thermal tolerance, body size, condition factor, spawning date and age at sexual maturation in various types of pedigrees (backcrosses between semi-inbred lines and outcrossed families). Although our initial efforts at map construction focused on simple sequence repeats (SSRs), the recent addition of amplified fragment length polymorphism (AFLP) markers has resulted in a significant increase in map density (approximately 300 in Arctic charr, 800 in rainbow trout, 600 in Atlantic salmon). The current maps are based on sex-specific analysis of linkage data to account for the marked differences in gene transmission between male and female salmonids. Analysis of SSR loci indicates that QTL for upper thermal tolerance and body size map to homologous chromosomal regions in Arctic charr and rainbow trout. Further, QTL for different traits sometimes co-occur on the same linkage groups in charr and trout suggesting the existence of single QTL with pleiotropic effects and/or close linkage of different QTL. Such analyses provide the basis for investigations into the study of genome evolution and genetic constraints