[Molecular evolution of the Thr-Gly region of the period gene in Drosophila and some dipterans].

In this study, the molecular evolution of the Thr-Gly region of the period gene was characterized, using dipteran groups with close, medium, and long distance phylogenetic relationship. No sexual selection or other positive selection was found to be acting on the Thr-Gly region. The evolutionary rate of the Thr-Gly region in nasuta subgroup was 10.4 x 10(-9) synonymous substitution/site/year. The divergence time of the nasuta subgroup of Drosophila was estimated to be 1-3 mya. A phylogenetic tree of Drosophila genus was reconstructed, which is well supported by evidences from archaebiological and biogeographical studies, The molecular evolutionary pattern of Thr-Gly region was discussed.