Variation of allozyme loci in populations of Drosophila melanogaster from the former USSR.

Variation of eight allozyme loci, Acph, Adh, Est-6, Est-C, alpha-Gpdh, Idh (NADP-dependent), 6-Pgd and Pgm, was studied in 20 populations of Drosophila melanogaster from the territory of the former USSR, including Eastern Europe, the Caucasus and Central Asia. Adh exhibited weak regression on latitude, longitude, and also on the temperature of the hottest calendar month in these localities. For seven other loci, no regular geographical pattern was found. Nei's coefficient of gene differentiation (GST) ranged from 0.010 (6-Pgd, statistically nonsignificant) to 0.178 (Idh) and was on average 0.058. The average Nei's genetic distance (D) between the populations was 0.011. It is suggested that this fairly low level of interpopulation differentiation for the examined loci except Idh may be explained by extensive gene flow in combination with natural selection.