The pleiotropic effect of selection for behavior on coat color in grey rats (Rattus norvegicus)

The effects of selection for a type of behavior relative to humans (tame and aggressive) on the intensity of coat color in agouti rats with the AAHH genotype were studied. Animals that were not under selection for behavior (wild animals) were used as the control. Morphometric analysis of the hair parameters that influence the intensity of coat color demonstrated that, on the one hand, polymorphism in the main coat color exists in the population of wild agouti rats, that is, both light and dark agouti animals exist. On the other hand, it was demonstrated that selection for a type of behavior in rats is accompanied by selection of animals that differ in the intensity of the main genetically identical coat color. Dark-colored animals are more prevelent among the aggressive animals, while light-colored animals prevail among tame animals. The association of the effects of selection for behavior with the modification of coat color is probably caused by the presence of common neurohormonal mechanisms for the regulation of these processes.