GENETIC-ANALYSIS OF COMBINATIONS OF THE L AWC(P1) MUTATION WITH VARIOUS ALLELES, OF AS-C GENES IN DROSOPHILA

Phenotypic expression of mutations within the leg-aristal-wing complex (lawc) locus involves alteration of the number and location of macroc haetae. In Drosophila, development of macrochaetae depends on products of the two proneural genes, achaete (ac) and scute (sc), constituents of the approximately 90-kb ac-sc gene complex (AS-C). Untranscribed r egions of AS-C involve enhancer-like cis-elements that are responsible for the local combination of some factors specifically determining ex pression of the ac-se genes in larval imaginal discs of Drosophila. In the present work, the frequency of appearance of additional macrochae tae was tested to analyze phenotypic exhibition of the temperature-sen sitive lawc(p1) allele. This mutation was also genetically analyzed in combination with various AS-C alleles involving alterations of transc ribed or cis-regulatory regions of this gene complex. A hypothesis tha t the lawc gene encodes a factor determining the specific expression o f the ac-sc genes is discussed.