a1 Department of Biological Sciences, The George Washington University, Washington, D.C. 20006
Many of the yellow alleles found in Drosophila melanogaster result in a unique pattern of phenotypic expression. These patterns follow the morphologically distinct cell types of the cuticle, so that for one allele all the bristles of the head and thorax might be mutant, while most of the fly appears wild type. A comparison of many different y mutants demonstrates that the yellow phenotype is expressed independently in most if not all the different cell types which form the cuticle. Control of this expression appears to reside at the yellow locus itself.
(Received February 11 1974)
p1 Present address: Laboratory of General and Comparative Biochemistry, Nationa Institute of Mental Health, Bethesda, Maryland 20014.