Other data on potential transgenerational genomic instability following irradiation are largely limited to males. Elevated frequencies of chromosome aberrations, micronuclei and lacI mutations have been reported in the F1 offspring of irradiated male mice and rats [30–34]. Transgenerational changes in somatic mutations were also observed by analyzing somatic reversions of the pink-eyed unstable mutation [35,36]. The results of these various studies suggested that a radiation-induced signal in the germ line of exposed males can be transmitted via the sperm to the offspring, resulting in an elevated mutation rate detectable in somatic cells. Moreover, studies by Dubrova and colleagues, using highly unstable expanded simple tandem repeat (ESTR) loci (originally termed minisatellites), showed that the radiation-induced genomic instability is not restricted to somatic cells but is also manifested in the germ line, resulting in elevated somatic and germline mutations rates in the offspring of exposed males [37–39].