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Widespread compensatory evolution conserves DNA-encoded nucleosome organization in yeast
Ephraim Kenigsberg1, Amir Bar, Eran Segal
1Department of Computer Science and Applied Mathematics, Weizmann Institute of Science, Rehovot, Israel.
Plos Computational Biology
|January 5, 2011
Summary
Genomic evolution in yeast reveals compensatory dynamics maintaining DNA A+T content. This widespread phenomenon, driven by weak selection, impacts most intergenic sequences, conserving quantitative genomic functions.
Area of Science:
- Evolutionary biology
- Genomics
- Molecular biology
Background:
- Organismal fitness relies on genomic information preservation, often assumed to involve specific locus conservation.
- Quantitative dispersed codes, integrating information from multiple genomic positions, are increasingly recognized but their evolutionary dynamics are unclear.
Purpose of the Study:
- To investigate the evolutionary dynamics of quantitative dispersed codes in yeast.
- To determine if compensatory evolution plays a role in maintaining genomic functions.
Main Methods:
- Utilized evolutionary modeling.
- Analyzed yeast polymorphism data.
Main Results:
- Observed compensatory dynamics in sequences affecting nucleosome occupancy in yeast.
- Demonstrated maintenance of heterogeneous A+T content through coupled A/T-losing and A/T-gaining substitutions.
- Found evidence that these dynamics result from weak selection.
Conclusions:
- Compensatory evolution is a widespread phenomenon in the yeast genome, affecting the majority of intergenic sequences.
- This contrasts with previous beliefs that it was limited to specific, epistatically linked loci.
- The derived model suggests compensation is inevitable for conserving quantitative and dispersed genomic functions.
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