Population-genetic study of Drosophila melanogaster from the Seychelles: frequency of alleles of allozyme loci and morpho-physiological traits,Populiatsionnno-geneticheskoe issledovanie Drosophila melanogaster Seǐshel'skikh ostrovov: chastoty alleleǐ allozimnykh lokusov i morfo-fiziologicheskie priznaki