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Homoplasmic yeast cells contain no selectable "hidden" mitochondrial alleles
1Department of Genetics, The Ohio State University, 43210, Columbus, Ohio, USA.
Current Genetics
|November 2, 2013
Summary
Mitochondrial DNA segregation in yeast (Saccharomyces cerevisiae) results in homoplasmic progeny. Even under strong selection, the lost mitochondrial allele is undetectable, suggesting its complete absence.
Area of Science:
- Molecular Biology
- Genetics
- Yeast Biology
Background:
- Yeast (Saccharomyces cerevisiae) zygotes can be heteroplasmic for mitochondrial alleles.
- Diploid progeny from such zygotes typically become homoplasmic for one allele.
- Homoplasmy is assessed by observing daughter cell phenotypes after subcloning.
Purpose of the Study:
- To investigate the fate of the lost mitochondrial allele in yeast progeny.
- To determine if the lost allele persists in a non-detectable state.
Main Methods:
- Inducing heteroplasmy in Saccharomyces cerevisiae zygotes.
- Subcloning diploid progeny to assess homoplasmy.
- Applying strong selection for the previously lost mitochondrial allele.
Main Results:
- Diploid progeny consistently segregated into homoplasmic daughter cells.
- Under strong selection for the missing allele, it remained undetectable.
- The lost allele was not detected even in a single copy.
Conclusions:
- Mitochondrial allele segregation in yeast is highly efficient, leading to complete loss of one allele.
- The absence of the lost allele, even under selection, suggests a robust segregation mechanism.
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