Environmental Health Centre 1 article published in JoVE Biology Transgenic Rodent Assay for Quantifying Male Germ Cell Mutant Frequency Jason M. O'Brien1, Marc A. Beal1, John D. Gingerich1, Lynda Soper1, George R. Douglas1, Carole L. Yauk1, Francesco Marchetti1 1Environmental Health Science and Research Bureau, Health Canada, Environmental Health Centre De novo mutations in the male germline may contribute to adverse health outcomes in subsequent generations. Here we describe a protocol for the use of a transgenic rodent model for quantifying mutations in male germ cells induced by environmental agents.