[Obtaining autosomal recessive mutations in the silkworm by exposure to nitrosomethylurea]

Mutagenic effect of N-nitrosomethyl urea (NMU) was studied in silkworm Bombyx mori L. Taking into consideration the specificity of the mutagen action, the main part of the work delt with the search for the optimum regime of the mutagen administration. The NMU effect is observed at different stages of the silkworm development by means of different methods. Maximal frequency of mutation in +re locus, obtained by the method of abdominal injection of the male-morth comprised 1.4%. Genetic analysis of the nature of the mutants obtained has revealed them to be point mutants.