Ocelli reduced or absent; ocellar and scutellar
bristles absent; interocellar microchaetae disrupted but frontals normal; postverticals short, thick, often with an adventitious pair between the normally placed postvertical bristles. Wing veins L3 and L4 converge, giving wing phenotype
much like fu although wing phenotype variable. Homozygous
lethal; lethality occurs during embryonic period (Hochman).
Shown to be a segment polarity gene; homozygous embryos exhibit loss of the naked cuticle in the posterior half of each
segment plus the anterior margin of the adjacent segment; most
dorsal pattern elements also eliminated, leaving a lawn of
fine hairs. Engrailed-antibody staining fails to detect a
subset of CNS neurons in Ce homozygotes that are normally
stained in wild-type embryos (Patel, Schafer, Goodman, and
Holmgren, 1989, Genes Dev. 3: 890-904). No maternal requirement of Ce+ for either oogenesis or embryonic phenotype
(Orenic, Chidsey, and Holmgrern, 1987, Dev. Biol. 124: 50-56). Lethal phenotype of Ce not complemented by l(4)17 or by
induced revertants of the wing phenotype of ciD (Orenic et
al.); pupal lethal in combination with ciD [Hochman, 1976, The
Genetics and Biology of Drosophila (Ashburner and Novitski,
eds.). Academic Press, London, New York, San Francisco,
Vol. 1b, pp. 902-28]. RK3.
ci: cubitus interruptus
Wings showing from no interruption (extreme left) to complete
absence (extreme right) of the cubital vein. From Stern and
Kodani, 1955, Genetics 40: 343-73.
Vein L4 shows one or more gaps both distal and proximal to posterior crossvein, generally nonterminal. Anterior
crossvein shortened or absent. Other gaps and scattered
branch veins in region of crossveins. At 19, nearly all flies
have a mutant phenotype; at 25, there is slight overlap with
wild type; at 30, virtually all flies are wild type. Dosage
effect such that ci/0 haplo-4's are more extreme than ci/ci
diplo-4's, which are more extreme than ci/ci/ci triplo-4's.
Suppressed by su(Hw)2 (Kotarski). For interactions of ci with
en, H, ve, and cg, see House (1953, Genetics 38: 199-214,
309-27; 1955, Anat. Record 122: 471; 1959, Genetics,
44: 516; 1961, Genetics, 46: 871). Expression of ci sensitive to genetic background; selection possible for more and
less extreme phenotypes (House and Yeatts, 1962, Genetics
47: 960); contribution of chromosome 2 more important than
that of 3 (House and Pernaveau, 1971, Genetics 68: s29).
Phenotypic effect visible in prepupa by absence of the longer
longitudinal vein. RK1 at 19 and higher rank with higher temperatures.
*ci+2: cubitus interruptus-wild-type isoallele
Homozygote wild type at 14 and 26. ci+2/Df(4)M wild
type at 26; shows some thinning and interruption of L4 at 14.
ci+2/ci wild type at 26; at 14, fewer flies show thinning or
interruption of L4 than ci+C/ci. ci+2/ciW shows significantly
greater amount of thinning and interruption of L4 than
ciD: cubitus interruptus-Dominant
Wings show interruptions of L4 in two
places: proximal to and distal to anterior crossvein. L5
also shows distal interruption. L3 and L5 thick. Considerable plexus effect and knotting of veins. Wings broader,
warped or concave upward, regularly extended, and bent backward. Alula fused with and in same plane as blade of wing.
Black dried haemolymph from axillary spiracle. Slight scalloping of inner wing margin, with hairs and tufts. Direction
and extent of temperature effects depends on genetic background (Scharloo). In general, no overlapping of wild type.
Inviable in combination with Ax/Ax or Ax/Y (House and Lutes,
1975, Genetics 80: 542-43). H/+ inhibits scalloping of ciD
but greatly enhances L4 interruption (House, 1959, Genetics
44: 516). Fully dominant in triplo-4's (Sturtevant, 1936,
Genetics 21: 448). Two doses of ciD reduce survival of
triplo-4 flies (Parker, 1969, Mutat. Res. 7: 393-407). Homozygotes lethal in embryo (Hochman, 1971, Genetics 67: 235-52).
Embryonic segment polarity disrupted; anterior portions of
segments with their denticle belts duplicated in mirror-image
fashion; posterior portions missing; each segment almost
entirely covered with denticles (Nusslein-Volhard and
Wieschaus, 1980, Nature 287: 795-801). Fine hairs eliminated
from dorsal abdominal segments; replaced with clear cuticle
and socketed denticles (Orenic, Chidsey, and Holmgren, 1987,
Dev. Biol. 124: 50-56). Embryonic CNS relatively normal
(Patel, Schafer, Goodman, and Holmgren, 1989, Genes Dev.
3: 890-904). Genotype of oocyte with respect to ciD without
effect on phenotype of progeny (Orenic et al.).
ciD/l(4)102ABc dies as embryo, ciD/l(4)102ABb as embryo or
larva; in ciD/Ce2 death usually delayed until pupal stage
(Hochman, 1971). Survival of ci/ciD/Df(4)M101-63a argues for
nonallelism or pseudoallelism of ci and ciD (Hochman, 1971).
ciW: cubitus interruptus of Wallace
Homozygote is extreme ci type. Wings sometimes
almost twice normal width, arclike, and virtually lack veins.
Often present is a well-organized pattern of venation in which
the posterior crossvein flows smoothly into L5. Legs lumpy,
sex combs larger than normal, antennae enlarged, eyes smaller,
and extra bristles present. Heterozygote shows gap in L4 in
80% of flies. ciW enhanced by H, en, and Cy (House, 1953,
Genetics 38: 669-70; 1959, Genetics 44: 516) and by Tp(4;Y)
(Benner, 1972, Genetics 71: s4). Temperature effect described
by House (1955, Genetics 40: 576). RK2.