Genetic variation in carotenoid pigment deposition in the red-fleshed and white-fleshed chinook salmon (Oncorhynchus tshawytscha) of Quesnel River, British Columbia

Inheritance of the ability to deposit coloured dietary carotenoid pigments in muscle tissue was examined in 16 seapen-reared families of chinook salmon (Oncorhynchus tshawytscha) from the Quesnel River, British Columbia. The progeny red:white ratio varied significantly among families in two sample periods but not between sample periods for individual families. There was no difference between the sexes in proportions of red and white individuals. Total carotenoid extraction of muscle tissue samples from 152 progeny revealed that white individuals contained less carotenoid per gram of tissue (0.24 ± 0.04 μg) than did red ones (3.37 ± 0.14 μg). Estimates of the heritability of flesh colour, when treated as a threshold trait, were 0.93 (sire component) and 0.71 (dam component). A genetic model that invokes two genetic loci, each with two alleles, was proposed to explain the inheritance of flesh colour in Quesnel River chinook salmon. At each locus, one copy of a "red-determining" allele is required for colour...