Variability of 5' and 3' untranslated regions of Dras1 gene in the Drosophila virilis species group. Anna I. Chekunova¹, Prokhor A. Proshakov¹, Maxim I. Barsukov¹, Ekaterina Sivoplyas¹, George N. Bachtojarov², Svetlana Yu. Sorokina¹, Vladimir G. Mitrofanov¹. 1) Dept Genetics, Koltsov Inst Dev Biol, RAS, Moscow, Russian Federation; 2) Mechnikov Research Institute of Vaccines and Sera, RAMS, Moscow, Russian Federation.

   Investigation of conservative genes polymorphism in groups of closely related species is particularly interesting from evolutionary point of view because the revealed variability should be neutral. Ras1 gene is highly conservative. Product of its expression - Ras1 protein - takes part in mitotic activity regulation of cell. Mutations in this gene frequently lead to cancerogenesis. Ras1 activity regulation is also evolutionary conservative. Previously, we studied the variability of several exons and introns of Dras1 gene in the drosophila virilis group, which serves as a convenient model for studying of molecular evolutionary processes at the early stages of divergence. In this part of study the nucleotide sequences of enhancer region of Dras1 gene and its 3- region were analyzed in the virilis species group. As sequences comparative analysis shows, the characters of evolution of these two sequence fragments greatly differ. Enhancer region of Dras1 gene revealed significant polymorphism presented both by nucleotide substitutions and indels of 1-22 bps of length. Alignment of this sequence fragment with the same fragment of D.melanogaster, D.mojavensis and D.grimshawi only was possible for short motives (approx. 10 nucleotides), which may be functionally important, such as DRE elements. The great amount of variable sites, including phylogeneticaly informative sites, was found among the virilis group species. In contrast, 3- region was much more conservative. The greater part of sequence polymorphism (including insertion of 9 bps that is nearby polyadenilation site) allows to distinguish the species at phylad and subphylad levels. Some substitutions were species specific. The study was supported by RFBR grant N 12-04-00926-a and the program of the Presidium of RAS Wildlife: Current status and problems of development.