Behavior genetic analysis of Water-T-Maze learning in inbred strains of mice,their hybrids,and selected second generation crosses

Summary The Water-T-Maze was used to investigate the genetically determined apparatus-dependent behavior of mice. Special importance was attached to the mode of inheritance involved. For this purpose we used NMRI, C3H/HeJ, Balb/c, Balb/cN, DBA/2, C57Bl/6 inbred mouse strains, together with their offspring and the F₂-hybrids of C3H/HeJ and DBA/2. Furthermore investigations were carried out to examine the effect of the environment on the expression of behavior. After these experiments had proved that there is a predominantly genetic derivation for behavioral expression, a possible relationship between the conditioning effect and the age of the animals was investigated. The animal's age has quantitative effects on the expression of behavior, but it does not lead to any qualitative behavioral changes. Nevertheless early conditioning of the animals apparently manifests itself in long-term memory. On the whole the mode of inheritance in Water-T-Maze learning appears to imply a polygene-dependent model in which clear dominant effects are present, as shown in the results of the F₂-generation. No sex-related differences were observed. In general, the results demonstrate a definite involvement of genetic factors in the areas of conditioning and behavior.