Petite mutation
Encyclopedia
petite is a mutant first discovered in the yeast
Saccharomyces cerevisiae
. Due to defect in the respiratory chain, 'petite' yeast are unable to grow on media containing only non-fermentable carbon sources (such as glycerol or ethanol), and form small anaerobic colonies when grown in the presence of fermentable carbon sources (such as glucose). The petite phenotype can be caused by the absence of, or mutations in, mitochondrial DNA
(termed "cytoplasmic petites"), or by mutations in nuclear encoded genes involved in oxidative phosphorylation. 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.
Yeast
Yeasts are eukaryotic micro-organisms classified in the kingdom Fungi, with 1,500 species currently described estimated to be only 1% of all fungal species. Most reproduce asexually by mitosis, and many do so by an asymmetric division process called budding...
Saccharomyces cerevisiae
Saccharomyces cerevisiae
Saccharomyces cerevisiae is a species of yeast. It is perhaps the most useful yeast, having been instrumental to baking and brewing since ancient times. It is believed that it was originally isolated from the skin of grapes...
. Due to defect in the respiratory chain, 'petite' yeast are unable to grow on media containing only non-fermentable carbon sources (such as glycerol or ethanol), and form small anaerobic colonies when grown in the presence of fermentable carbon sources (such as glucose). The petite phenotype can be caused by the absence of, or mutations in, mitochondrial DNA
Mitochondrial DNA
Mitochondrial DNA is the DNA located in organelles called mitochondria, structures within eukaryotic cells that convert the chemical energy from food into a form that cells can use, adenosine triphosphate...
(termed "cytoplasmic petites"), or by mutations in nuclear encoded genes involved in oxidative phosphorylation. A neutral petite produces all wild type
Wild type
Wild type refers to the phenotype of the typical form of a species as it occurs in nature. Originally, the wild type was conceptualized as a product of the standard, "normal" allele at a locus, in contrast to that produced by a non-standard, "mutant" allele...
progeny when crossed with wild type.
petite mutations can be induced using a variety of mutagens, including DNA intercalating
Intercalation (chemistry)
In chemistry, intercalation is the reversible inclusion of a molecule between two other molecules . Examples include DNA intercalation and graphite intercalation compounds.- DNA intercalation :...
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.