Related Experiment Videos
DNA mismatch repair and synonymous codon evolution in mammals
1Institute of Cell, Animal and Population Biology, University of Edinburgh.
Molecular Biology and Evolution
|January 1, 1994
Summary
Differences in DNA repair efficiency do not explain codon usage variation in mammalian genes. This study found no evidence supporting the mismatch repair hypothesis for synonymous codon bias.
Area of Science:
- Molecular Biology
- Genomics
- Evolutionary Biology
Background:
- Synonymous codon usage varies among mammalian genes within a genome.
- Differences in DNA mismatch repair efficiency have been proposed as a cause for this variation.
Purpose of the Study:
- To test the hypothesis that DNA mismatch repair efficiency drives synonymous codon usage differences in mammalian genes.
- To model the relationship between substitution rates and G+C content under varying mismatch repair efficiencies.
Main Methods:
- Developed a model of DNA mismatch repair.
- Predicted the relationship between silent-site substitution rates and G+C content based on the model.
- Empirically tested predictions using 58 primate and artiodactyl genes.
Main Results:
- The model predicted a decline in substitution rate with increasing G+C content if mismatch repair is G+C biased.
- Empirical data from primate and artiodactyl genes showed no such decline in substitution rate with G+C content.
- Analysis indicated a very narrow parameter range for mismatch repair to explain codon usage differences.
Conclusions:
- Variation in DNA mismatch repair efficiency does not account for differences in synonymous codon usage among mammalian genes.
- The proposed hypothesis is not supported by the empirical data and model analysis.