Homozygotes die during the late embryonic and first larval instar stages. Females containing homozygous germline clones are fertile. 43% of the female progeny of homozygous female germline clones have a Minute-like bristle phenotype; bristles are short and often thinner than normal and scutellar bristles are occasionally absent. One side of the scutellum and thorax is often more affected than the other. 41% of these females have fused tergites. 25% of the male progeny of homozygous female germline clones have a Minute-like bristle phenotype, of which 23% also have fused tergites. 11% of the male progeny of homozygous female germline clones have rotated genitalia, which protrude from the body. In extreme cases, 180o rotation is seen.
Somatic clonal analysis indicates that M(2)21AB is required for cell proliferation or growth during development of the eye imaginal disc.
Mutant has lost the developmental delay, the Minute characteristics and the female temperature sensitive sterility previously described in FBrf0028903.