Abstract
The recessive mutant ft (2L at 12.0) contains vacuolae in the cells of larval salivary glands. In the chromosomes of these cells a puff is formed in region (24D/E) corresponding to the locus of the gene ft. This puff appears or disappears as the vacuolae are present or absent. There are also secondary puffs in other chromosomes of ft/ft larvae, this indicates an interaction between ft and other loci of similar activity.
