Adult escapers display a strong cos wing phenotype.
Hemizygous lethal but homozygous viable. In homozygotes, wing duplications are evident. cos2/cos7 and cos6/cos7 flies display local pattern duplications on the anterior margin of the wings and halteres. cos6/cos7 flies are sick and sterile. Embryos derived from mutant germ line clones have normal segmentation but a deletion phenotype in each segment such that virtually the entire denticle belt is deleted, leaving only one or two of the anterior-most rows of denticles. The width of the denticle belts is also reduced. A few embryos show an anterior open phenotype.
class II allele
Complements the viable cos alleles, unless flies are simultaneously heterozygous for "Cos" mutants.
Grau & Simpson.
Allelic series: cos3 >= cos2 >= cos1 = cos4 = cos5 >= cos6 >= cos7.