dp alleles have variable effects on wing length and
shape and on the thoracic cuticle. Presence of wing phenotype
indicated by o = oblique in the allelic designation and of
thoracic phenotype by v = vortex or cm = comma. The wing
effect is an oblique truncation affecting the margins of the
first and second posterior cells in weak alleles and reducing
wings to approximately half normal length in extreme genotypes, where the truncation is more nearly perpendicular to
the long axis of wing. Margins remain intact; angle between
veins L2 and L5 increased, and intercrossvein distance
decreased. Phenotype resembles rudimentary. Thoracic phenotype comprises five types of hypodermal irregularities: first
vortices, second vortices, commas, pre-episternal pits, and
posterior invagination; all five have the form of pits, eruptions, or raised pits of the cuticle (Metcalfe, 1970, Genetics
65: 627-54). First vortices are hypodermal pits or eruptions
located posterolaterally on the scutum; they disrupt the
acrostichal rows, resulting in surrounding whorls of microchaete. Second vortices are located anterolaterally on the
scutum and resemble first vortices morphologically. Commas
are comma-shaped depressions at the anterior margin of the
scutum. The pre-episternal pit is in the pre-episternal plate
immediately anterior to the sternopleural chaetae, which sometimes exhibit disturbed orientation (Metcalf, 1969, DIS
44: 91). The posterior invagination occurs between the
laterotergite plate and the metanotum (Metcalf, 1969); different alleles exhibit different combinations of these traits.
Musculature attached to disturbed regions of the cuticle often
degenerates (Metcalfe, 1970). Some alleles show reduced body
size and small weak legs (dph, dpobw females, dpolv/dpov).
Phenotypic expression enhanced by increased temperature during
development; wing and thorax effects show dominance when
heterozygotes exposed to increased temperatures at 12-16 and
8-10 hr of pupal life, respectively (Blanc and Child, 1940,
Physiol. Zool. 13: 65-72). Normal larvae fed 6-azauracil
produce adults with oblique phenocopies; 6-azauracil feeding
suppresses dp (Rizki and Rizki, 1965, Science 150: 222-23),
su(r) enhances the oblique phenotype (Stroman, 1974, Hereditas
78: 157-68). The four genotypes studied [dpo2, dpovN, dpv2,
and dpv; e(dpv)] show increased orotate phosphoribosyl
transferase activity during third larval instar and enhanced
incorportion of labeled glucose into chitin (Blass and Hunt,
1980, Mol. Gen. Genet. 178: 437-42). Many alleles are lethal
when homozygous; they are identified by l in the allelic
designation. Lethal stages vary among alleles, e.g., dpolv is
embryonic lethal; dplv1, and dplvI die at the egg-larval boundary; dplm homozygotes die primarily at larval ecdysis between
the first and second larval instar with some death at hatching
and at ecdysis of second-instar larvae; dpobm homozygotes die
mostly at hatching but a few die during first and second larval instars (Metcalfe, 1971, Genet. Res. 17: 173-83).
In Me/+ heterozygotes, many dp alleles show a dominant
oblique effect when heterozygous for dp+ and dp; dpv is an
exception (Carlson, 1959). dpv homozygotes normal; show
thoracic phenotype only if third chromosomes homozygous for
e(dpv).
