Evidence for a high mutation rate at rapidly evolving yeast centromeres
1University of Manchester, UK. douda.bensasson@manchester.ac.uk
BMC Evolutionary Biology
|July 20, 2011
Summary
Centromere DNA evolves rapidly in yeast, 3 times faster than unconstrained DNA. This rapid evolution is likely due to increased mutation rates, not gene conversion, possibly linked to centromere chromatin structure.
Area of Science:
- Genetics
- Evolutionary Biology
- Molecular Biology
Background:
- Centromeres are crucial for cell division but evolve rapidly across diverse organisms.
- The simple point centromeres of Saccharomyces yeasts offer a tractable model for studying rapid centromere evolution.
Purpose of the Study:
- To investigate the evolutionary rates and mechanisms driving rapid centromere evolution in yeast species.
- To differentiate between potential causes of rapid centromere evolution, such as meiotic drive or increased mutation rates.
Main Methods:
- Comparative genomic analysis of centromere DNA sequences from Saccharomyces cerevisiae strains.
- Population genomic data analysis from Saccharomyces paradoxus.
- Examination of recombination patterns and mutation spectra within and around centromeres.
Main Results:
- Centromeres in both Saccharomyces cerevisiae and Saccharomyces paradoxus evolve approximately three times faster than selectively unconstrained DNA.
- High levels of polymorphism suggest rapid evolution is not driven by meiotic drive.
- Limited evidence for intra-centromeric recombination, but clear evidence in flanking regions.
- Centromeric mutation spectrum aligns with spontaneous mutation patterns genome-wide.
Conclusions:
- Rapid centromere evolution is a widespread phenomenon in yeast.
- Gene conversion is unlikely to be the primary driver of rapid centromere evolution.
- A generalized increase in mutation rate, potentially due to unique centromeric chromatin structure, is the likely cause.
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