| Summary: | Electrophoretic variability was scored among individuals supplied by the S.A.T.M.A.R. hatchery (Barfleur, France), where all broodstock was selected on the basis of rapid growth. The first generation (F1) comprised 14 females and 4 males, of which 17 were analysed by polyacrylamide gel electrophoresis. Thirty individuals (or less) of the second generation (F2) were analysed in the same manner. The following enzymes were studied: Phosphoglucoisdmerase (PGI), Isocitrate de-hydrogenase (IDH), Sorbitol de-hydrogenase (SDH), Superoxyde dismutase (SOD), Phosphoglucomutase (PGM), Esterases (EST), Leucine aminopeptidase (LAP). These enzymes represented 12 loci, of which 6 were polymorphic (PGI, SDH, PGM, Est 2, Est 4, LAP 2). The rate of heterozygosity of the Fl and F2 individuals were compared. The number of alleles was not different in the two generations and the total heterozygosity observed for the 12 loci was 0.20 in Fl and 0.18 in F2. Thus, there has been no loss of genetic variability over one generation in spite of the small number of spawners. This result may provide further evidence that fast growth rate and enzyme heterozygosity may be positively related.
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