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Quantitative Comparison of cis-Regulatory Element (CRE) Activities in Transgenic Drosophila melanogaster
Published on: December 19, 2011
Adaptive evolution of non-coding DNA in Drosophila.
1Section of Ecology, Behavior and Evolution, Division of Biological Sciences, University of California San Diego, La Jolla, California 92093, USA. pandolfatto@ucsd.edu
Nature
|October 21, 2005
Summary
A significant portion of non-coding DNA in Drosophila is functionally important, evolving under both constraint and positive selection. This suggests adaptive changes in non-coding DNA are common in evolution.
Area of Science:
- Evolutionary biology
- Genomics
- Molecular evolution
Background:
- Eukaryotic genomes contain a large proportion of non-coding DNA with largely unknown functions.
- Understanding the evolutionary dynamics of non-coding DNA is crucial for a complete picture of genome evolution.
Purpose of the Study:
- To investigate the evolutionary rates and selective pressures acting on various classes of non-coding DNA in Drosophila.
- To determine the extent of functional importance and adaptive evolution in non-coding genomic regions.
Main Methods:
- Comparative analysis of DNA sequences from different Drosophila species.
- Application of an extended McDonald-Kreitman test to differentiate between purifying and positive selection.
- Estimation of evolutionary constraint by comparing non-coding DNA evolution to synonymous sites.
Main Results:
- Non-coding DNA regions (intergenic, UTRs, introns) evolve slower than synonymous sites, indicating selective constraint.
- A significant excess of divergence over polymorphism suggests adaptive evolution in these regions.
- Estimates indicate 40-70% of non-coding nucleotides are under constraint, with 20-60% of divergence driven by positive selection.
Conclusions:
- A large fraction of non-coding DNA is functionally significant and shaped by both purifying and adaptive evolution.
- Adaptive evolution in non-coding DNA may be more prevalent than previously thought in Drosophila melanogaster evolution.
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