trx1 heterozygous adults show occasional homeotic transformation in the abdomen (A5 to A4 transformation, indicated by loss of pigmentation in A5).
Heterozygous adults display transformation of the fifth abdominal segment towards the likelihood of A5, and frequently show a partial haltere-to-wing transformation.
trx1 flies show a haltere to wing transformation.
trx1/trxB11 flies show transformations of wing to haltere; 49% show strong transformation, 34% show weak transformation and 16% show no transformation.
trx1/trxE2 flies show transformations of wing to haltere; 57% show strong transformation, 34% show weak transformation and 9% show no transformation.
Homozygotes show homeotic transformation phenotypes. They show an average of 7.16 transformations/fly (males were scored for a possible 29 transformations, females were scored for a possible 26 transformations). These phenotypes have an increased penetrance at 25oC. 0.8% of heterozygous adults show at least one transformation phenotype. trx1 in combination with other trx alleles produces patchy transformations that occur most frequently in anterior compartments. trx1/trxred-P6 hemizygotes show phenotypes that suggest decreased Scr function (transformation of T1 structures to a T2 identity), decreased Ubx function (transformation of T3 to T2), decreased abd-A function (transformation of A2-A7 to A1) and decreased Abd-B function (transformation of posterior abdominal segments to more anterior abdominal identities). Scr group transformations include the development of mesothoracic tibial preapical bristles or mesothoracic tibial apical bristles on the prothoracic tibia, reduced numbers of sex comb teeth (in males), development of sternopleural bristles or katepisternal bristles on the T1 segment. Ubx group transformations include haltere to wing, metathoracic laterotergite to scutum, the development of T3 sternopleural bristles, mesothoracic tibial preapical bristles or mesothoracic tibial apical bristles on the metathoracic tibia. abd-A group transformations include, the development of A1 type bristles on abdominal tergites 2. Abd-B group transformations include, the pigmentation of abdominal tergites 5 to 6 in males, and enlargement of abdominal tergite 7.
Loss of trx in enF4 flies enhances the wing phenotype; severe disruption to posterior wing development. These flies are also female sterile.
Temperature shift experiments reveal temperature sensitive period is prior to gastrulation.
Transformation of the posterior abdominal segments to anterior abdominal segments.
Flies homozygous for trx1 show a variety of partial homeotic transformations <up>ventral prothorax and metathorax to mesothorax and second to seventh abdominal segments to first abdominal segment (Ingham and Whittle, 1980)</up>. Penetrance of the transformation phenotype is stronger in hemizygotes than homozygotes and increases as the temperature is raised from 18oC to 25oC. At the higher temperature, the penetrance of the mutant offspring of trx1/trx1 females is almost 100%, while mutant offspring of trx1/+ females show only about 50% penetrance. The temperature-sensitive period occurs prior to hatching. Ingham (1980) noted the following abnormalities in extreme trx1 mutants: (1) Extra bristles between humerus and coxa and on the distal tibia of the first leg; (2) Similar changes on the third leg; (3) Loss or reduction of transverse bristle rows, and, in males, decrease in number of sex comb teeth on the first leg; (4) Replacement of halter disk derivatives by wing blade, notal and scutellar structures; (5) Rotated genitalia and abnormal tergite pigmentation in male flies. 75% of heterozygotes with a red- deletion or with the lethal allele trx3 are lethal, either as larvae or pupae (Ingham, 1981); the heterozygotes that survive show cuticular transformations of the ventral prothorax and the metathorax, an extra mesonotum developing posterior to the normal one and anteriorly-directed abdominal transformations (Ingham, 1985a). recessive; viable in homozygotes