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Maintenance of a Drosophila melanogaster Population Cage
Published on: March 15, 2016
Selection on codon usage and base composition in Drosophila americana.
Sophie Marion de Procé1, Kai Zeng, Andrea J Betancourt
1Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK. sdeproce@staffmail.ed.ac.uk
Biology Letters
|August 19, 2011
Summary
This study reveals stronger selection on codon usage bias in Drosophila americana than on GC/AT variants in introns. Evidence suggests recent population expansion necessitates revising previous selection estimates.
Area of Science:
- Evolutionary genetics
- Population genetics
- Molecular evolution
Background:
- Drosophila americana was previously assumed to have a stable demographic history.
- Recent evidence indicates a population expansion in Drosophila americana.
- This expansion necessitates re-evaluation of prior selection strength estimates.
Purpose of the Study:
- To estimate selection strength on codon usage and biased gene conversion (BGC) in Drosophila americana.
- To account for a recently detected population expansion in demographic models.
- To compare selection pressures on introns versus coding sequences.
Main Methods:
- Utilized a polymorphism dataset from X-linked loci (introns and coding sequences) in Drosophila americana.
- Employed a maximum-likelihood method to detect recent population expansion.
- Analyzed selection on codon usage and GC/AT variants.
Main Results:
- Detected evidence for natural selection or BGC favoring GC over AT variants in introns, with stronger effects in GC-rich introns.
- Found evidence for selection on codon usage bias in coding sequences.
- Observed that selection on codon usage bias is significantly stronger than GC/AT selection in introns.
Conclusions:
- The demographic history of Drosophila americana is not stable, featuring a recent population expansion.
- Selection on codon usage bias is a more potent evolutionary force than GC/AT selection in introns within this species.
- Previous estimates of selection strength require revision due to the newly understood population dynamics.
