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Mitochondrial recombination in crosses of iso- and anisomitochondrial Saccharomyces cerevisiae
Abstract:
Mitochondrial mutants resistant to erythromycin, neomycin and monomycin were isolated. Mitochondria were transmitted from different natural strains to the cells of the same nuclear genotype. In bifactorial crosses of such isochromosomal and anisomitochondrial yeasts we tested random samples of diploid colonies. The distribution of mitochondrial markers in parent and recombinant classes has been shown to occur unequally. The asymmetry of parent and the polarity of recombinant classes were observed to differ in different mitochondrial mutants. Anisomitochondrial strain crosses proved that mitochondrial origin essentially influenced both the parent and recombinant classes distribution and the susceptibility of the transmission to the effect of mating type locus. One can distinguish between 'homo- and heterosexual' cross combinations in terms of recombination polarity. The new type of mitochondria was found to occur with high frequency of transmission to the zygote progeny of markers resistant to erythromycin but not of markers resistant to neomycin. The problem of 'sex' in mitochondria is discussed.
Insights
Mitochondrial genetics reveals unequal inheritance of antibiotic resistance markers in yeast crosses. Mitochondrial origin significantly impacts marker distribution and transmission, influencing recombination patterns.
Area of Science:
- Mitochondrial genetics
- Yeast genetics
- Molecular biology
Background:
- Mitochondria possess their own genetic material, distinct from nuclear DNA.
- Mitochondrial inheritance in eukaryotes is typically maternal, but complex interactions can occur.
- Understanding mitochondrial genetics is crucial for studying cellular function and evolution.
Purpose of the Study:
- To investigate the inheritance patterns of mitochondrial drug resistance markers in yeast.
- To analyze the influence of mitochondrial origin on genetic recombination and transmission.
- To explore the role of the mating type locus in mitochondrial inheritance.
Main Methods:
- Isolation of mitochondrial mutants resistant to erythromycin, neomycin, and monomycin.
- Construction of isochromosomal and anisomitochondrial yeast strains.
- Bifactorial crosses and analysis of random diploid colony samples.
- Assessment of mitochondrial marker distribution in parent and recombinant classes.
Main Results:
- Unequal distribution of mitochondrial markers in parent and recombinant classes was observed.
- Asymmetry in parent classes and polarity in recombinant classes varied among mitochondrial mutants.
- Mitochondrial origin significantly affected marker distribution and transmission susceptibility to mating type locus effects.
- A novel mitochondrial type showed high transmission frequency for erythromycin resistance markers, but not neomycin resistance markers.
Conclusions:
- Mitochondrial origin is a critical factor influencing the inheritance and recombination of mitochondrial genes.
- The mating type locus plays a role in modulating mitochondrial transmission.
- Distinct inheritance patterns for different antibiotic resistance markers suggest complex regulatory mechanisms.
- The findings contribute to the understanding of mitochondrial 'sex' and genetic exchange.