Specific elimination of mitochondrial DNA from Chlamydomonas by intercalating dyes.

Minute colony mutations in C. reinhardtii are induced with 100% efficiency by intercalating dyes such as acriflavin and ethidium bromide. These mutants form small colonies on petri plates because they undergo only 8-9 mitotic divisions before growth ceases. In liquid media without the dye the mutants show gross alterations in mitochondrial structure and function. Here we demonstrate that induction of minute mutations is accompanied by the specific loss of mitochondrial DNA. We also provide evidence that the transmission of the minute colony phenotype in crosses can be explained in terms of uniparental transmission of mitochondrial DNA by the mt- parent.