Body color varies from shining black to slightly
darker than wild type, depending on allele. Puparia much
lighter than wild type. Classifiable throughout larva period
by darkened color of spiracle sheaths (Brehme, 1941, Proc.
Nat. Acad. Sci. USA 27: 254-61). Viability lowered to about
80% wild type. Heterozygotes for dark alleles have slightly
darker body color than normal. For interaction with other body
color mutants, see Waddington (1941, Proc. Zool. Soc. London,
Ser. A 111: 173-80). Postulated to encode β-alanyl dopamine
synthetase, a 90-kd enzyme that requires ATP and MgCl2 to
catalyze the formation of N-β-alanyl dopamine from β alanine
and dopamine; β alanyl dopamine absent from newly eclosed e
flies (Wright, 1987, Adv. Genet. 24: 127-222); β alanine and
dopamine accumulate in pupae and pharate adults, dopamine to
twice normal levels, in e and e11 homozygotes; levels return
to normal in older adults (Hodgetts, 1972, J. Insect Physiol.
18: 937-47; Hodgetts and Konopka, 1973, J. Insect Physiol.
19: 1211-20). Unable to utilize β alanine in tanning of
puparium. Labeled β alanine or uracil injected into e pupae
remains in hemocoel, not incorporated into pupal case as in +;
light-colored pupa result; e/+ intermediate in these respects.
Only newly emerged + adults incorporate uracil or β alanine
into cuticle; e flies and older + flies do not; β alanine
toxic to the latter two types (Jacobs, 1968, Biochem. Genet.
1: 267-75). Defect in tanning leads to spongey cuticle which
responds to β alanine administration (Jacobs, 1980, Biochem.
Genet. 18: 65-76). Phenylthiocarbamide inhibits development
of e11 homozygotes more than wild type; reverse is true for
inhibition by silver chloride; heterozygotes intermediate in
both cases. Mixtures of the two inhibitors affect heterozygotes to a greater extent (Kroman and Parsons, 1960, Nature
186: 411-12). Electroretinograms of e flies abnormal; lamina
potential reduced or absent (Hotta and Benzer, 1969, Nature
222: 354-56). Threshold for phototaxis 200-fold higher than
that for wild type; high sensitivity (retinulae 1-6) optomotor
threshold 500 times normal and high acuity (retinulae 7 and 8)
optomotor threshold ten times normal [Heisenberg, 1972, Information Processing in the Visual Systems of Arthropods
(R. Wehner, ed.). Springer-Verlag, Berlin, Heidelberg, and
New York, pp. 265-68]. e flies more sensitive to polarized
light than wild type (Heisenberg, 1972). Abnormal distribution of uptake of 3H-GABA by the lamina ganglionaris described
by Campos-Ortega (Cell Tissue Res. 147: 415-31). Reduced
mating success compared to wild type (Rendel, 1951, Evolution
5: 226-30). Courtship frequently aborts owing to mismounting
by male [Crossley and Zuill, 1970, Nature (London)
225: 1064-65]; relative mating success increased in dark
(Kyriacou, 1981, Anim. Behav. 29: 462-71) but not according
to Crossley (1970, DIS 45: 170). Courtship shows deficiency
in wing vibration; low proportion of sine song and long intra-pulse interval; e/+ outsings +/+ (Kyriacou, Burnet, and Connolly, 1978, Anim. Behav. 26: 1195-1206). RK1.