[Mutagenic effect of radiation on mice, subjected to gamma-irradiation during the embryonic period. III. Frequency of coat color mosaics among mice, heterozygous for recessive mutations, subjected to irradiation during the early periods of embryogenesis].

The frequency of coat colour and coat length mosaics was investigated among heterozygous for 7 or 6 recessive mutations mice, that were gamma-irradiated at doses of 100 or 200 r at different stages of embryogenesis. Only 4 mosaics with gray coat spots were found among 1399 animals that developed from embryos irradiated at doses of 100--200 r within 4,5--13,5 days of embryogenesis. 3 of these mosaics were found among 756 animals irradiated at the dose of 100 r at the 10,5 day of embryogenesis (0,35%). This frequency is considerably lower that the frequency of coat colour mosaics obtained by other authors in similar experiments.