Chromosomal instability in NZB/BL mice. A dominant trait.

The descendance of 2 lines from NZB/bl mice which differ by the frequency of chromosome breaks has been studied. The analysis of reciprocal crosses and of "back cross" shows that the character of the chromosome breaks is perhaps dominant. This result is correlated with the observation that the autoimmunity (17) and viral expression (1, 13, 17) are also dominant.