Induction of meiotic chromosomal malsegregation in yeast.

A system to detect chromosome number abnormalities occurring during meiosis in Saccharomyces cerevisiae is described. It is based on selection of spores carrying 2 multi-marked chromosomes V. Each step of the technical procedure is critically analyzed and the origin of some biases discussed. Selection and subsequent genetic analysis allow the estimation of the frequency of spontaneous and induced diploid and aneuploid n + 1 (diplo-V) spores. Data are reported concerning the effect of 53 chemical compounds. The great majority of active chemicals induce diploid clones while a minority cause non-disjunction of chromosome V.