GENETICS OF UNSTABLE ALLELES OF THE X-CHR OMOSOME GENES ISOLATED FROMNATURAL-POPULATIONS OF DROSOPHILA-MELANOGASTER DURING THE OUTBURST OFMUTATION YELLOW IN 1982 TO 1991 IN UMAN

In 1982, a local increase of frequency of mutation yellow-2, which las ted for a decade, occurred in a population of Drosophila melanogaster from Uman' (Ukraine). Genetic properties (phenotypic difference, mutab ility, and peculiarities of complementation) of alleles yellow-2, isol ated from the population during the mutation outburst, and of their re vertants, were studied. Allelic diversity, which reflected molecular d ifferences in allele structure, was shown to appear, In addition to mu tation yellow, isolated in 1990 from the Uman' population, mutational properties of other sex-linked genes (dusky, miniature, rudimentary, s inged, and vermilion) isolated from natural populations in 1986 to 199 0, were analyzed. Based on these data, the conclusion was drawn that t he presence of unstable alleles in populations is not a sufficient con dition for mutation outbursts. Comparative analysis of properties of t he the alleles, obtained in different periods of the outburst, continu es.