Homozygous bip2Fa4a does not enhance the frequency of haltere to wing transformation seen in TrlR85/TM2, Ubx130 flies (2.73% of flies show transformations, compared to 2.48%), but it does enhance the severity of the transformation.
Double heterozygous lolalk02512 Ubx130 flies do not show significant increase in the expressivity of the Ubx phenotype. lolalk02512/+; Trl13C/Ubx130 flies display a higher frequency (18%) of strong haltere-to-wing transformations compared to Trl13C/Ubx130 siblings (6.3%). This increased transformation is often accompanied by a notal transformation.
56% of Ubx130, Trl13C double heterozygotes have halteres that quite heterogeneous in size and larger than Ubx130 alone. 63% of Ubx130, Df(3L)Aprt-21 double heterozygotes have halteres that quite heterogeneous in size and larger than Ubx130 alone. 78% of Ubx130, Df(3L)Aprt-21, Trl13C triple heterozygotes have halteres that quite heterogeneous in size and larger than Ubx130 alone, also exhibiting a stronger phenotype than any two of the alleles used. The haltere becomes a wing -like structure with wing veins and hairs on the wing margin.
Ubx130/TrlR85 flies have a low penetrance of haltere to wing transformations and notal transformations. The penetrance of these phenotypes is significantly enhanced by heterozygosity for Df(2R)Δ18, even though the phenotypes are present at a very low penetrance (<0.5%) in Ubx130, Df(2R)Δ18 double heterozygotes.
Flies doubly heterozygous for Ubx130 and Trl13C show larger halteres than Ubx130 heterozygotes alone, and with variable penetrance and expressivity show homeotic transformations of the haltere and postnotum. When zae(bx) is added to the doubly heterozygous combination the Ubx phenotype is enhanced.
Heterozygotes have slightly enlarged halteres compared to wild type. Trl13C+/+Ubx130 double heterozygous flies have larger halteres than Ubx130 heterozygotes. Homeotic transformations include a low frequency of patches on the haltere and postnotum that develop like wing and notum tissues respectively.