Selection of wild gray rats for domestication (tame behavior) resulted
in a sharp increase in the frequency of heterozygotes at the h allele
of hooded, the main locus of rat depigmentation. The observed effect
of the selection on the manifestation of the h allele is compared with
similar effects giving rise to piebaldness in other animals subjected
to experimental domestication. The results are discussed in terms of
genetic specificity of piebaldness and of the selection vector.