When single cell mutant clones are made, duplications of class I neurons.
en and nub expressing multidendritic (md) neurons in the dorsal cluster are moderately over produced in bib1 mutants.
Homozygous mutant somatic clones in the eye contain occasional extra photoreceptor cells. Ommatidia often have extra photoreceptor cell rhabdomeres.
Homozygous clones in adult flies have moderately increased numbers of macrochaetae and microchaetae. These bristles have normal sockets innervated by single neurons.
Homozygous embryos have an increased number of cardiac precursor cells.
Embryos exhibit fused muscles in patterned arrangements, particularly in the more dorsal regions of the embryo. The birefringent is clearly correlated with the expansion of the CNS and PNS, and the loss of epidermis and the degree to which myoblast fusion occurs. Where myoblast fusion fails conspicuous clusters of mesodermal cells are formed and if epidermal territories are expanded cells in these clusters may be recruited to fusion.
Sensory neurons, foregut, trachea, endoderm, and larval midgut are wild type.
ac protein distribution in bib1 embryos show ac expression is not restricted to a single cell of an ectodermal cell cluster, instead most cells of the cluster retain ac expression at a high level, enlarge, delaminate and become neuroblasts.
bib1 expression was not modified by the presence of ASC loss-of-function mutations.
Homozygous clones induced in the eye and thoracic imaginal discs show epidermal development indistinguishable from wild-type.
Intermediate embryonic neurogenic phenotype. CNS hypertrophy and epidermal defects are evident in all mutants.