FlyBase curator comment: this entry is used to capture phenotypic information when the particular allele (or allele combination) used by the author could not be determined but the context of the experiment suggests that the phenotype being described is some kind of loss of function.
Heterozygotes have a variably reduced number of macrochaetae and occasionally microchaetae, although the bristle sockets are present.
Polygenic modifier factors present on the O chromosome of D.subobscura that affect the expression of the Dsub\Baunspecified phenotype produce very large selective effects on the Dsub\Ba locus.