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The evolutionary demography of duplicate genes.
1Dept. of Biology, Indiana University, Bloomington, Indiana 47405, USA.
Journal of Structural and Functional Genomics
|July 3, 2003
Summary
Gene duplication rates are similar to mutation rates, but duplicates are quickly lost. Most duplicates do not gain new functions, but may drive genome evolution and reproductive isolation.
Area of Science:
- Evolutionary biology
- Genomics
- Molecular evolution
Background:
- Gene duplication is considered a primary driver of evolutionary novelty.
- The rates of gene duplicate origin, loss, and preservation remain poorly quantified.
Purpose of the Study:
- To estimate the rates of gene duplication and loss in eukaryotes.
- To investigate the evolutionary fate and functional consequences of gene duplicates.
- To understand the role of gene duplication in genome size variation and speciation.
Main Methods:
- Applied steady-state demographic techniques to analyze age distributions of duplicate genes.
- Censused duplicate genes across seven completely sequenced eukaryotic genomes.
Main Results:
- Estimated the average eukaryotic gene duplication rate at approximately 0.01 per gene per million years.
- Determined the average half-life of duplicate genes to be around 4.0 million years.
- Observed significant interspecific variation in duplication/loss rates, influencing genome size via a birth-death process.
- Found that most duplicates undergo relaxed selection, with few showing directional selection; long-lived duplicates are under strong purifying selection.
Conclusions:
- The origin of new gene function is a rare outcome of duplication.
- Gene duplication's primary evolutionary impact may involve generating microchromosomal rearrangements, potentially leading to reproductive isolation.
- The dynamics of gene duplication and loss significantly shape genome evolution and species divergence.