Genetic analysis of the dumpy complex locus in Drosophila melanogaster: complementation, fine structure and function.

An extensive genetic analysis of the dumpy locus is presented. This study includes complementation, fine structure mapping and allelic interaction. A number of complementing recessive lethals of the dp complex have been genetically mapped. Two alleles of the ol(v) type that complement l alleles map to the left portion of the locus. A number of olv alleles that complement both l and lv lethals map within the right portion of the locus.--Fine-structure analysis demonstrated that both olv and o alleles are distributed among various subloci. Evidence for spacer regions between subloci is presented.--An extensive discussion of the data considers whether the locus is unicistronic or multicistronic. The conclusion reached is that the locus is not a single functional cistron. The possibility of a single cistron encoding a multifunctional polypeptide is discussed.--The hypothesis is proposed that the left portion of the map and the l mutations function as regulatory sequences and that the right portion of the map encodes structural sequences.