en¹/en^Adv-1 flies have a cleft scutellum and en-type posterior ewing phenotypes as well as the 'additional vein' phenotype seen in en^Adv-1/+ flies.

2% of homozygotes and 5% of en¹/en⁵⁴ flies have a gap in the fourth wing vein at 25^oC.

Homozygotes exhibit a variety of wing vein alterations in the posterior compartment of the wing. Transheterozygotes with en^Enci have a posterior specific wing phenotype: bristles characteristic of the anterior wing margin are present on the posterior wing margin. Males have duplicated sex combs on the prothoracic legs.

Heterozygotes with en^spt display the en and spermatheca phenotypes at 25^oC.

Mutation has no effect on the hh^Mrt phenotype.

Viable.

Coordinate mutant.

hh^bar3 in combination with Df(2R)en^E/en¹ causes a phenotype reminiscent of a weak dpp mutation is produced, narrowing of the space between wing veins 3 and 4. Posterior wing clones affect adjacent cells of the anterior compartment and cause an overall reduction in wing size.

Additional bristles in the second leg.

Heterozygotes with en^Xho23 and en^Sac27 display wing vein abnormalities.

Homozygous adults have abnormal wings, with a posterior to anterior transformation. The sex comb on the male prothoracic leg is partially duplicated posteriorly. The posterior wing is grossly disrupted in en¹/en² transheterozygotes, rarely having an organised fourth or fifth vein. The sex comb on the male prothoracic leg is duplicated posteriorly, more distal leg segments are fused and terminal claws are sometimes missing. The arista and other anterior elements of the antenna are often duplicated.

The posterior wing is an abnormal shape in homozygous flies. The posterior wing veins have a variable disrupted pattern, with the anterior crossvein (ACV) often being absent or reduced and vein III often appearing slightly thickened. The campaniform sensillum associated with the ACV is often absent, while the campaniform sensilla of vein III may be increased in number. Campaniform sensilla are often found in the posterior wing, where they may or may not be associated with vein tissue. Many posterior margin hairs are transformed into socketed bristles, some of which are similar to the thick middle row bristles of the anterior margin. Parts of the posterior margin are thickened into vein tissue similar to the anterior margin in some wings. The alar lobe carries socketed bristles. There is a cleft in the scutellum. Approximately five irregularly arranged "secondary" sex-comb teeth are found on the posterior tarsus of the foreleg. en¹/Df(2R)en-A or en¹/Df(2R)en-B hemizygotes are sterile. They have a less distorted posterior wing blade than en¹ homozygotes. The posterior wing venation varies from wild-type in occasional cases to severely disrupted. The posterior margin is never thickened to form vein tissue, and carries fewer socketed bristles than en¹ homozygotes. These bristles tend to look like double row or dorsal or ventral triple row bristles. The alar lobe is wild-type. The scutellum is broader than wild-type and sometimes shows an incipient cleft. en⁵⁷/en¹, en¹⁰/en¹, en⁵⁴/en¹ or en⁵⁸/en¹ flies have wild-type shape wings and a wild-type scutellum. Vein III appears thickened and tends to have a posteriorwards bulge about halfway along its length. The anterior crossvein (ACV) is often reduced or absent. Small plexae of vein tissue tend to occur close to the ACV and the posterior crossvein. Vein IV is frequently interrupted and often carries campaniform sensilla. Bristles are occasionally seen in the posterior row, but they never have the characteristics of the middle triple row.

Severe thoracic morphological defects.

Shows wing to haltere transformation in en¹/en²⁸.

Male en¹ homozygotes have abnormal genitalia, with a reduction in the number of clasper teeth, rudimentary dorsal parameres of the penis apparatus, and often incomplete rotation of the penis apparatus. Viable heteroallelic combinations with other en alleles show a more extreme phenotype, with a reduction in the genital arch process, hypandrium and hypandrial phragma as well. Extra genital arch and anal plate bristles are sometimes seen. Female flies carrying en¹ and another en mutation show variable genital abnormalities, ranging from no abnormalities, to reduced dorsal and ventral vaginal plates, which sometimes have a giant bristle. Extra bristles and pigmentation are sometimes seen on the eighth tergite.

At 29^oC the third segment of the antenna is larger than wild-type in homozygous flies, and a bristle close to the border is often enlarged. This phenotype is enhanced by the M(3)65F mutation. en¹/en² transheterozygotes have abnormal antennae, the phenotype increasing at higher temperatures (25 or 29^oC). At 29^oC the posterior compartment of the second segment is almost always abnormal, having extra anterior-like bristles which are often arranged in a mirror-image symmetry with respect to the anterior compartment. The third segment is usually larger than normal and is often bilobed. Approximately half the antennae having a bilobed third segment also have an extra arista. en¹/en² transheterozygotes also have abnormal wings; at 17^oC they are grossly enlarged, there is scalloping of the posterior margin, and the triple rows of anterior-like bristles are poorly formed. At 29^oC the wings are not enlarged and a well-formed triple row develops on the posterior margin.

Homozygous clones in the wing are frequently lost in the posterior but not the anterior compartment.

Duplications of transverse rows in female prothoracic leg, extra bristles in mesothoracic and metathoracic tarsi.

Clones of en¹ cells of posterior compartment origin fail to respect anterior-posterior compartment border in wing disc as do mwh¹ clones in wing discs of en¹ homozygotes.

In males, extra sex comb often present smaller than normal and in mirror-image position in posterior compartment.

viable

en¹, ph-p^lac has visible | recessive phenotype

en¹/en⁵⁴, ph-p^lac has visible | recessive phenotype

en¹ is an enhancer of phenotype of ci¹

en¹ is an enhancer of phenotype of ci⁵⁷

en¹ is an enhancer of phenotype of ci³⁶

en¹, ph-p^lac has wing vein L4 phenotype

en¹/en⁵⁴, ph-p^lac has wing vein L4 phenotype

cg¹, en¹ has wing vein L4 phenotype