Comparison of parental behavior and offspring's anxiety behavior using a reciprocal F1 hybrid model

Emotional behavior can be characterized by interactions between genes and environments, especially in the developmental period. However, in mice, the effects of paternal care on offspring's emotional development are not well understood even in cases in which the male mice show stable paternal care to the pups. In this study, we used a reciprocal hybrid model of C57BL/6 and BALB/c mice, which show different parental behaviors and emotional responses, and compared the emotional responses in pups in their adulthood by using the elevated plus-maze test. It was found that inbred male mice showed intensive parental behavior toward their pups, especially as parental contact behavior, and that the licking/grooming behavior of males was dependent on the strain of the female they were paired with. Also, BALB/c pairs showed less parental contact behavior than C57BL/6 pairs. In the elevated plus-maze test, BALB/c males and females showed higher anxiety behavior, and reciprocal hybrid offspring showed intermediate values between C57BL/6 and BALB/c mice. Although no significant difference was found in the parental care that offspring received and anxiety-related behavior between the two reciprocal hybrid strains, BALB/c pairs showed less parental contact behavior toward the pups as compared to C57BL/6 pairs, which would be associated with the higher anxiety-related behavior exhibited in the adulthood of BALB/c strain.