ASSOCIATION BETWEEN THE REGULATORY LOCUS PGM-1R-ASTERISK AND LIFE-HISTORY TYPES OF JUVENILE ATLANTIC SALMON (SALMO-SALAR)

We sampled three juvenile life-history types of Atlantic salmon (Salmo salar) from Western Arm Brook, Newfoundland, to test whether a regula tory gene variant PGM-1rb is associated with accelerated life-history development. Seven nonmigratory parr populations from the Miramichi R iver, New Brunswick, and the Margaree River, Nova Scotia, were also sa mpled. Previous studies with rainbow trout (Oncorhynchus mykiss) indic ate that the liver-specific regulatory gene variant PGM-1r6 is associ ated with faster embryonic and life-history development. We found no a ssociation between variation at PCM-1r and body weight, fork length, gonadal development, and smelt age. However, the frequency of PGM-1r was significantly higher in males than in females for combined life-hi story types from Western Arm Brook. These results suggest that PGM-1r is sex linked or under strong sex-specific selection in this populati on. Furthermore, populations with higher frequencies of PGM-1rb tende d to have higher frequencies of precocious maturation in males.