Protein variation and duplicate loci in the Atlantic salmon, Salmo solar L

A natural population of Atlantic salmon, Salmo salar L. was screened for genetic variation at 59 protein loci, using a sample of parr, the juvenile freshwater stage. The mean heterozygosity per locus, estimated at 0·033 ± 0·014, is similar to that described in other salmonid species but low for fish species in general. Variation was observed at AAT, IDH, MD–ME, GLO, ADA, and SDH loci. The methods described should prove useful in stock discrimination and in producing salmon for restocking and sea-rearing. The observed extent of gene duplication is discussed in relation to the evolution and systematics of the salmonid fishes.