Interaction of Y-chromosomal and autosomal gene(s) in the development of intermale aggression in mice.

It has been suggested that the Y chromosome of DBA/1Bg mice makes an incremental contribution to their aggressive behavior and to that of the C57BL/10 female X DBA/1 male F1 hybrids. To test this hypothesis, a congenic stock of C57BL/10 with the DBA/1 Y chromosome was developed by the backcross system of breeding; the stock is designated C57BL/10-Y1. There were no significant differences in aggressive behavior between the congenic C57BL/10 and C57BL/10-Y1. However, the hybrid B10D1 F1 and D1B10-Y1 F1 had identical aggression scores, and both of these were more aggressive than the hybrid D1B10 F1. These findings support the hypothesis that there is an interaction between DBA/1 Y chromosomes and autosomes in the development of intermale aggression of these mice.