Paternal effects on the development of social behavior in Mus musculus.

In order to extend the determination and description of effects of the father's phenotype on the development of social behavior in male mice, we tested 24 males from each of 2 highly inbred strains of Mus musculus, A/J and C57BL/6J. Approximately 1 week before the birth of the subjects, we replaced natural fathers with a foster parent such that, within each strain, 8 subjects had preweaning experience with same-strain males, 8 with other-strain males, and 8 with same-strain females, in addition to their natural mothers. Observations of social behavior were conducted at 21, 50, and 60 days of age. The results showed effects of the foster parent's phenotype on the development of social exploration in both strains and, possibly, on agonistic behavior in C57BL/6J mice. The different effects in the 2 strains indicate mechanisms dependent on genotype.