Biochemical Population Genetics of Pacific Halibut (Hippoglossus stenolepis) and Comparison with Atlantic Halibut (H.hippoglossus)

Abstract

The gene products of 35 protein-coding loci were examined for Mendelian variation in three samples of Pacific halibut (Hippoglossus stenolepis) and one sample of Atlantic halibut (H. hippoglossus). Contingency table analyses of allelic frequencies for five polymorphic loci revealed no significant frequency differences between the Bering Sea and the Gulf of Alaska but detected significant Ada-2 frequency differences between these regions and Japan. Average genetic distance between the samples of Pacific halibut was 0.0002 ± 0.0007, and gene diversity analyses showed that 98.7% of the total genetic variation was contained within populations, 0.4% was due to differences between the Bering Sea and the Gulf of Alaska, and 0.9% was due to differences between these regions and Japan. These results are consistent with a larval drift, juvenile migration model of population genetic structure where not all juveniles home to their natal areas. Nei's genetic distance between Pacific and Atlantic halibut was 0.162 ± 0.073, and the molecular clock hypothesis suggests that these species became reproductively isolated from one another in the Pliocene between 1.7 and 4.5 million years ago.