Coat color differences and runway learning in mice.

Abstract

Parents and their offspring from a heterogeneous stock (HS/Ibg) of mice were tested for acquisition and extinction of a running response. A polynomial regression function was fitted to the learning curves of each individual and the resulting coefficients were used as the variables in subsequent analyses. Mice homozygous recessive at either thea, b ord locus, i.e., with coat color phenotypes of nonagouti, brown or dilute, did not differ significantly on any of the variables from animals heterozygous or homozygous for the corresponding dominant alleles (agouti, black or full color, respectively). In addition, none of the possible interlocular interactions was significant. Albinos, however, acquired and extinguished the response more slowly than did pigmented mice. Segregation at thec locus was found to account for 10 percent and 24 percent of the additive genetic variance in acquisition and extinction, respectively. These results, taken in conjunction with other findings on the impaired learning ability of albinos, suggest that there is central involvement in the albino syndrome.