Hemizygous male testis are smaller than those of wild type males, few germ cell develop past primary spermatocytes. Ovaries of homozygous females are also smaller than those of wild type. Examination of the ovaries revealed they retain a large number of eggs, only a few are laid.

Homozygous germ-line clones do not give rise to vitellogenic egg primordia at 29^oC.

Imaginal discs of homozygous larvae are morphologically normal but differentiate abnormally.

Homozygous larvae raised at the non-permissive temperature show extensive overgrowth of the wing discs. The discs have convoluted epithelial outgrowths, mainly in the wing pouch region. The number of gap junctions is reduced in these discs.

At permissive temperatures (20^oC or lower), approximately half the expected number of homozygotes eclose, the remainder dying as pharate adults. Those that emerge are sterile, the ovaries of mutant females do not mature, while the reproductive system of males show no obvious morphological defects. They also have other slight abnormalities affecting the derivatives of the eye-antenna, wing, and leg discs. At 22^oC all homozygotes die as pharate adults, with greatly reduced heads, often with duplicated antennae and palp structures. The wings, halteres and legs are also abnormal. At 25-29^oC no metamorphosis occurs. The eye-antenna disc is reduced to a thread of tissue, while the antennal region is either absent or partially duplicated. The wing and haltere discs are larger than normal and develop additional folds. Eye-antennal discs transplanted into wild-type hosts at 25^oC show extreme abnormalities.

temperature-sensitive At 20^oC about half the expected number of homozygotes eclose, the remainder dying as pharate adults; those that emerge are sterile, ovaries failing to mature, testes appearing morphologically normal; they also exhibit other slight abnormalities such as extra sex-comb teeth and defective wing margins. At 22^oC all flies die as pharate adults with greatly reduced heads, often with duplicated antennal and palpal structures. No metamorphosis accompanies development at 25^oC; the eye disc is virtually missing, whereas the wing and haltere discs are severely hyperplastic; disc effects autonomous in transplants. Temperature-shift experiments demonstrate a temperature-sensitive period lasting from the beginning of the second instar until the end of pupation. The 24-hr pulses of 27^oC during development reveal that the various phenotypic consequences of homozygosity for this allele have different TSP's. hyd¹ wing discs used to demonstrate that extra cellular proliferation is insufficient to induce transdetermination (Shearn et al., 1984). Density of gap junctions in hyperplastic imaginal wing discs markedly reduced (Ryerse and Nagel, 1984); in shift-up experiments, reduction in gap junctions precedes the onset of tissue hyperplasia (Ryerse and Nagel, 1985). Cell death also observed in wing discs as early as twelve hours following application of restrictive temperature (Sedlak, 1986). Mitosis normal (Gatti and Baker, 1989).