Genome-wide acceleration of protein evolution in flies (Diptera)
1 Institut für Genetik der Universität zu Köln, 50674 Köln, Germany
2 Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK
3 European Molecular Biology Laboratory, 69012 Heidelberg, Germany
BMC Evolutionary Biology 2006, 6:7 doi:10.1186/1471-2148-6-7Published: 25 January 2006
The rate of molecular evolution varies widely between proteins, both within and among lineages. To what extent is this variation influenced by genome-wide, lineage-specific effects? To answer this question, we assess the rate variation between insect lineages for a large number of orthologous genes.
When compared to the beetle Tribolium castaneum, we find that the stem lineage of flies and mosquitoes (Diptera) has experienced on average a 3-fold increase in the rate of evolution. Pairwise gene comparisons between Drosophila and Tribolium show a high correlation between evolutionary rates of orthologous proteins.
Gene specific divergence rates remain roughly constant over long evolutionary times, modulated by genome-wide, lineage-specific effects. Among the insects analysed so far, it appears that the Tribolium genes show the lowest rates of divergence. This has the practical consequence that homology searches for human genes yield significantly better matches in Tribolium than in Drosophila. We therefore suggest that Tribolium is better suited for comparisons between phyla than the widely employed dipterans.