A Search for Radiation-Induced Recessive Sex-Linked Lethal and Detrimental Mutations in Immature Germ Cells of the House Mouse (MUS MUSCULUS ).

HE total genetic risk with respect to recessive lethal mutations in mammals can only be assessed if the mutability of sex chromosomes as well as autosomes is known. Therefore, a three-generation test was done in order to determine the incidence of recessive sex-linked lethal and detrimental mutations in mice. The frequency of autosomal recessives will be determined in subsequent experiments. This first report only concerns the radiation-induction of recessive X-linked lethal and detrimental mutations in spermatogonia and oocytes; a further paper now in progress will deal with radiation-induced recessive sexlinked lethals and detrimentals in spermatozoa and spermatids. In order to obtain a clearer picture of the overall level of genetic damage, evidence for the possible induction of other mutations besides sex-linked lethals is also presented.