Distribution of ultraviolet light irradiated mitochondrial genomes during meiosis in yeast.

Clones derived from ascospores from ultraviolet irradiated diploid cells were examined for the genetic determinants or respiratory properties. Approximately 10% of the cells produced petites of mitochondrial origin at the dose applied. Among 13 asci which produced mitochondrial petites with high frequencies, 6 asci of uniparental type, 0 grandes : 4 petites, were observed. Furthermore, most of the petite spore clones from each individual uniparental ascus showed similar levels of suppressiveness and of mitochondrial gene retention. From these results it is suggested that a single mitochondrial genome participates meiosis in yeast.