Aging and diethylstilbestrol-induced aneuploidy in male germ cells: A transgenic mouse model

The incidence of aneuploidy in male germ cells was evaluated by analyzing e xtra marker chromosome(s) signal(s) in round and/or hook spermatids of tran sgenic mice. Two types of transgenic mice were used as models. The inserted foreign DNA (lambda-gt10LacZ shuttle vector and/or pSVc-myc plasmid) was l ocated at the middle of the long arms of chromosome 2 (lambda DNA) and/or c hromosome 8 (c-myc). The number of marker chromosomes present could easily be detected after fluorescence in situ hybridization (FISH) in testicular c ells. The frequency of spontaneous aneuploidy of chromosome 2 was similar i n round spermatids of lambda and lambda-myc mice. Differential involvement of chromosomes 2 and 8 was observed in both round and hook spermatids. The frequency of spontaneous aneuploidy in round spermatids was higher than tha t in hook spermatids, The frequency of aneuploidy of marker chromosomes was significantly higher in older mice (2 years old) than in younger ones. Die thylstilbestrol (DES)-induced aneuploidy was dose dependent, and was not in fluenced by the stage at which germ cells were treated with DES. These resu lts demonstrate the usefulness of a transgenic mouse model for the study of aneuploidy in germ cells.