Latent meiotic anomalies related to an ancestral exposure to a mutagenic agent.

When urethan is administered to cytologically normal F(2) progeny descended from grandsires exposed to ethyl methanesulfonate, meiotic anomalies in the forms of site-specific X-chromosome deletions and bivalent associations are noted in spermatocytes of male Armenian hamsters examined 6 and 8 days after treatment, respectively. These latent anomalies are initiated and retained in a premutated state for two generations after the ancestral exposure to ethyl methanesulfonate, the additional impetus required to complete the mutational processes being supplied by urethan.