On the retinal mediation of genetic influences in color preferences of Japanese quail.

The hypothesis that the pigmentation of retinal oil droplets is the morphological target of genetically induced change in the early color preferences of the Japanese quail (C. coturnix japonica) was examined and rejected. Subjects were drawn from the fourth generation of genetic selection for preferences between blue and red, and they were compared according to genetic lines of origin and the presence or absence of pigmentation in their retinal oil droplets. Pigmentation was manipulated by raising parents on carotenoid-free diet. Results indicate a uniform shift toward red preference in all subjects with history of carotenoid deprivation regardless of genetic background, and no change in the magnitude of differences between genetic lines. The data suggest that retinal oil droplets mediate intensity discrimination in the photopic range rather than the perception of variations in light wavelength.