Detection of lateral asymmetry in the C-bands of mouse-embryo chromosomes exposed in utero to mitomycin C.

Chromosomes from 10-day mouse embryos were C-banded and examined for aymmetric bands between sister chromatids. No occurrences of lateral asymmetry (LA) were observed in this series. However, when 10-day embryos were exposed in utero to a single maternal injection of 10 mg/kg mitomycin C 4--5 h prior to metaphase arrest with colcemid, a significant level of asymmetric C-banding was demonstrated in their chromosomes. As many as 4 LAs per cell were seen in 2 of the 50 metaphase spreads examined.