Inheritance of the white-red (Kohaku) color complex in ornamental (koi) carp (Cyprinus carpio L.)

Abstract

Color variability was investigated in three normal (amphimictic) and three meiotic gynogenetic progenies obtained from white-red (kohaku, according to Japanese classification) koi parents. All the amphimictic and gynogenetic progenies consisted of three color types - white, white-red and red. The ratio of colors depended on the relative coverage by red patches in the kohaku parents. The lowest percentage of red fish and highest proportion of white fish were recorded in progeny obtained from kohaku parents with relatively weak development of the red color. The percent coverage by red patches was measured in a sample of thirty or sixty white-red fish from each amphimictic progeny and the distribution of color classes within the sample was determined. The distribution of the sample, together with the white:white-red:red ratio in the total progeny, was used to estimate the color class distribution in the entire progeny (including the solid white and solid red individuals). In two of the amphimictic progenies, the fish clearly divided into two groups: non-red (solid white and white-red) and solid red fish. Appearance of these groups might be explained by the existence of some major color-determining gene(s), which determine(s) the background color (either white or red) of the individual fish. It is also suggested that the development of red patches in fish with a white body background is controlled by many genes with alleles that either maintain the white color or induce the appearance of red patches.