Transmission of petite phenotypes in Saccharomyces cerevisiae

(a) Wild-type Mutant nuclear genes nuclear genes Mutations in nuclear genes exhibit 2:2 segregation. (b) Wild type Segregational petite 00 2 wild type 2 petite Progenyofpetiteandwid—typephenotypesareproduoed ina2:2 ratio, indicating that segregational petite mutations are in nuclear genes. (1:) Wild type Neutal petite All wild-type progeny Progeny do not exhibit the petite phenotype, indicating that neutral petite mutants are not transmitted. Examination of neutral petite mutants indicates that they lack most or all mitochondrial DNA . (d) Wild type Suppressive petite to l 0000 All petite progeny Petite mitochondrial DNA dominates. and all progeny exhibit the petite phenotype. Examination of 51W petite mutants indicates that they havedeletionsofonwportionsof their nitod'iondrial DNA.