[DNA polymorphism of Drosophila genes and factors determining it]

The data on variation of DNA sequences in genes of Drosophilidae are reviewed. Intraspecific polymorphism and interspecific divergence of DNA nucleotide sequences are shown to be characteristic of most genes. The level of intraspecific polymorphism and interspecific DNA divergence and the degree of correlation between them depend on the mode, intensity, and direction of natural selection, as well as on the evolutionary history of the genes and species. The evolutionary role of synonymous and nonsynonymous nucleotide substitutions in DNA is analyzed. Genes responsible for the reproduction and genes controlling other functions are compared in respect to their variation.