Genetic mapping in Atlantic salmon (Salmo salar) and brown trout (Salmo trutta)

• Main Author: McGowan, Colin
• Format: Thesis
• Language: English
• Published: Memorial University of Newfoundland 1996
• Subjects: Atlantic salmon; Salmo salar
• Online Access: https://research.library.mun.ca/9186/; https://research.library.mun.ca/9186/1/McGowan_Colin2.pdf

Segregation analysis of polymorphic genetic markers was performed using the hybrid progeny of a brown trout (Salmo trutta) x Atlantic salmon (Salmo salar) cross. Three types of genetic markers, 1) RAPDs (randomly amplified polymorphic DNA), 2) microsatellites and 3) ESTs (expressed sequence tags) were examined. -- 1) Of the 271 random primers tested, 151 (56%) generated distinct, reproducible band patterns. A total 893 loci were scored, of which 126 could be attributed to the Atlantic salmon component of the genome and 173 to that of the brown trout. The majority (594) of loci were held in common by both parents. Three and 13 heterozygous loci were identified in the Atlantic salmon and brown trout parents, respectively. All of the markers segregated in a normal (1:1) manner. No linkage was observed in Atlantic salmon. Thirteen significant (P<0.05) pair-wise associations were identified in brown trout, five of which were highly significant (P<0.001). -- The RAPD procedure was also used for bulked segregant analysis of Atlantic salmon male and female DNA, to search for a sex-specific marker. A total of 1152 loci were screened using 200 different primers; however none were tightly linked to a male sex determining factor. -- 2) Two hybrid families were screened for polymorphisms at 14 microsatellite loci which have been described in previous studies. Seven and eight heterozygous markers were identified in the Atlantic salmon and brown trout parents, respectively. Segregation ratios of variant alleles in the hybrid offspring, were normal (1:1) in all but one case. In brown trout, seven significant (P<0.05) linkages were detected among microsatellite and RAPD loci, three of which were highly significant (P<0.001). In Atlantic salmon, five significant (P<0.05) linkages were identified, three of which were highly significant (P<0.001). Of three tightly linked microsatellite pairs identified in Atlantic salmon, only two are conserved in brown trout. -- 3) The partial sequences of 41 ESTs, isolated from ...