The genetics of some second chromosome melanotic tumour mutants ofDrosophila melanogaster

Abstract

SummaryThe genetic relationships of the available second chromosome melanotic tumour mutants inDrosophila melanogasterhave been investigated. Complementation tests demonstrate the existence of new alleles of thetu bwlocus and show thattu-Wandtu-gare alleles. The data suggest that there is a minimum of three major gene loci on the second chromosome involved in tumorigenesis. A number of modifier genes were found which affect the penetrance of the major tumour genes analysed. These and the problems they cause in mapping the low penetrant tumour genes are discussed. It has not been possible to maptu-48a, tu- Wandtu-gaccurately, due largely to the presence of modifier genes. It appears that the genetic basis for melanotic tumour formation is complex.