Genetic divergence at the NAD+-dependent malic enzyme locus in Atlantic salmon from Europe and North America

The distribution of genetic variation for NAD+ malic enzyme (ME*) polymorphism in the Atlantic salmon was assessed in both anadromous and resident populations. The analysis revealed a major allelic divergence between North America and Europe. The *80 variant occurred in 39 of 40 North American samples, ranging in frequency from 0 to 0·515. In contrast, it was detected in only three fish from two of the 35 European locations analysed. Eleven fish from two rivers in north-west France had the *110 variant. While heterogeneity among North American populations was significant, no regional differentiation was apparent and anadromous and resident salmon were not found to differ.