Petite mutation

Overview
petite (p-) is a mutant first discovered in the yeast Saccharomyces cerevisiae. The 'petite' yeast has little or no mitochondrial DNA, and forms small anaerobic colonies when grown on media. A neutral petite produces all wild type progeny when crossed with wild type.

petite mutations can be induced using a variety of mutagens, including DNA intercalating agents, as well as chemicals that can interfere with DNA synthesis in growing cells. Mutagens that create petites are implicated in increased rates of degenerative diseases and in the aging process.