A method for determining the statistical significance of mutation frequencies

Abstract

AbstractA method is devised for determining the statistical significance of the difference between a mutation frequency observed after treatment with a potential mutagen and its control frequency. This procedure, however, can be used only when the respective control value is based on large and reliable material (“stable” controls), a requirement that seems to be met in at least part of the systems used for mutagenesis screening. The procedure proposed has some advantages when compared with the 2 and the KASTENBAUM‐BOWMAN test, the most important one being that it can be employed when these two tests cannot (because of expected frequencies <5 in the 2 test and limited tabulations of the N and p values in the KASTENBAUM‐BOWMAN test). After explaining the procedure, an instruction how to carry it out is presented and illustrated by two examples (recessive sex‐linked lethal mutations in Drosophila melanogaster and dicentric chromosomes in human lymphocytes).