Abstract
The genetics of allelic variation for NADP-dependent isocitrate dehydrogenase (IDH-s) found in the supernatant of liver and white muscle extracts of rainbow trout (Salmo gairdneri) was examined. Twenty progeny from each of 50 controlled matings were examined for IDH phenotypes. Progeny data clearly indicated that the IDH-s variation in the muscle is controlled by two loci—one fixed and one with two alleles producing molecules of different electrophoretic mobilities. IDH-s variation in the liver is controlled by two disomic loci which code for four alleles. No linkage between the loci controlling IDH-s in the liver and the loci controlling it in the muscle was detected.