A multispecies approach for comparing sequence evolution of X-linked and autosomal sites in Drosophila Journal Article

Author(s): Vicoso, Beatriz; Haddrill, Penelope R; Charlesworth, Brian
Article Title: A multispecies approach for comparing sequence evolution of X-linked and autosomal sites in Drosophila
Abstract: Population genetics models show that, under certain conditions, the X chromosome is expected to be under more efficient selection than the autosomes. This could lead to 'faster-X evolution', if a large proportion of mutations are fixed by positive selection, as suggested by recent studies in Drosophila. We used a multispecies approach to test this: Muller's element D, an autosomal arm, is fused to the ancestral X chromosome in Drosophila pseudoobscura and its sister species, Drosophila affinis. We tested whether the same set of genes had higher rates of non-synonymous evolution when they were X-linked (in the D. pseudoobscura/D. affinis comparison) than when they were autosomal (in Drosophila melanogaster/Drosophila yakuba). Although not significant, our results suggest this may be the case, but only for genes under particularly strong positive selection/weak purifying selection. They also suggest that genes that have become X-linked have higher levels of codon bias and slower synonymous site evolution, consistent with more effective selection on codon usage at X-linked sites.
Keywords: Species Specificity; Molecular Sequence Data; Evolution, Molecular; Sequence Analysis, DNA; Drosophila; nonhuman; species difference; Natural selection; gene mutation; Drosophila melanogaster; molecular evolution; X chromosome; autosomal inheritance; codon; Drosophila affinis; drosophila pseudoobscura; drosophila yakuba; insect genetics; sex chromosomal inheritance; X chromosome Drosophila Proteins; Genes, Insect; Genes, X-Linked
Journal Title: Genetical Research
Volume: 90
Issue 5
ISSN: 0016-6723
Publisher: Cambridge University Press  
Date Published: 2008-10-01
Start Page: 421
End Page: 431
Sponsor: B.V. was supported by the Portuguese Foundation for Science and Technology, P.R.H. is supported by the Natural Environmental Research Council (UK) and B.C. was supported by the Royal Society (UK)
DOI: 10.1017/S0016672308009804
Open access: no