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General Information
D. melanogaster
FlyBase ID
Feature type
Associated gene
Associated Insertion(s)
Carried in Construct
Also Known As
mw+, P[w+, cre], P[w+,cre], ff#1
Key Links
Allele class
Nature of the Allele
Allele class
Mutations Mapped to the Genome
Additional Notes
Associated Sequence Data
Progenitor genotype
Nature of the lesion

4.15kb SpeI fragment of the w gene that carries a deletion of a large part of the first intron and the regulatory region is reduced to 300bp preceding the transcription start site.

Allele components
Product class / Tool use(s)
Regulatory region(s)
Encoded product / tool
Expression Data
Reporter Expression
Additional Information
Marker for
Reflects expression of
Reporter construct used in assay
Human Disease Associations
Disease Ontology (DO) Annotations
Models Based on Experimental Evidence ( 0 )
Modifiers Based on Experimental Evidence ( 0 )
Comments on Models/Modifiers Based on Experimental Evidence ( 0 )
Disease-implicated variant(s)
Phenotypic Data
Phenotypic Class
Phenotype Manifest In
Detailed Description

Males carrying w+mC in a w[+] background show comparable levels of courtship discrimination as Oregon-R males (showing higher levels of courtship towards decapitated females than towards decapitated males).

groups of naive males carrying w+mC in a w[+] background do not show chaining behaviour under daylight conditions, the same behaviour as is seen in Oregon-R males.

Uninsulated w+mC insertions (in a w[-] background) exhibit a wide range of eye colours, depending on the site of transgene insertion.

piwi, aub and spn-E are suppressors of repeat-induced silencing, as seen at heterochromatic tandem arrays of insertions of the P{lacW} transposon.

Eye colour: approximately 10% of P{GMroX1} transgenic stocks show sex-specific eye pigmentation patterns; in many cases mini-w expression is very low or silent in females but in the same lines, males express mini-w, often in mosaic sectors. The addition of a Y chromosome does not overcome the silencing seen in the females. Several of the P{GMroX1} lines show pairing-sensitive repression; showing significantly less eye pigmentation when homozygous than when hemizygous.

Eye colour: Expression of w+mC can restore pigment levels in the eyes of w1118 flies. No pairing-sensitive repression is seen; flies carrying two copies of w+mC have darker eyes than than heterozygotes carrying one copy of w+mC.

Transfection of the w+mC as part of the P{Ubi-GFP.D} construct, followed by heat shock, leads to male mutants that show an increase in male-male courtship compared to wild-type flies.

Eye colour: flies carrying w+mC in a w1118 background have eye colours ranging from yellow to red, depending on the P{CaSpeR-3} insertion strain used.

Heat induced expression of Scer\GAL4hs.PB in P{UAS-lacZ.U/l5} flies does not affect eye pigment levels.

Light affects basal male courtship: males are inhibited by white light

Eyes are light yellow.

Male-male courtship occurs between flies following ectopic expression of w+mC. Male-male courtship behaviour increases with age, flies 1 week old or older show high levels of courtship compared to one day posteclosion males. Olfactory, visual and gustatory responses are not affected by heat shock. Surgical ablation of the antenna and/or maxillary palps, or the wings has no effect on male-male courtship. Under red light male-male courtship is substantially reduced, restoration of white light increases courtship. For all classes of surgically treated flies red light diminishes courting activity. Male-male courtship is not due simply to an absence of rejection behaviour (wing flicking) as heat shocked males will court a non-w+mC male exhibiting rejection behaviour. Also the courting is not due to increased sexual attractance as non-w+mC males will not court heat shocked w+mC males.

Transformants carrying one copy of w+mC have more lightly pigmented eyes than flies carrying two copies.

Partially restores pigmentation in w- eyes. Heat shock during a period late in development of flies also carrying P{GAL4::Pc-Hsp70} exhibit a uniform reduction or abolition of eye pigmentation. Heat induction earlier in development does not affect eye pigmentation.

Fully dosage compensated on the X chromosome but only partly dosage compensated on the autosomes. Around 50% of X linked inserts display hyper dosage compensation, also observed for wsp1 and wa.

The w+mC mutation shows incomplete dosage compensation when inserted in the second or third chromosome (comparison of heterozygous males and homozygous females). The w+mC mutation of P{yp1,2,mini-w} or P{otu-lacZ.R} insertions into the X chromosome shows complete or hyperdosage compensation, such that hemizygous males have either equal or greater level of pigmentation than females.

Transformant heat shocked males exhibit homosexual courtship behaviour.

Variegated expression of w occurs when the minigene is present in repeat arrays. Variegation is particularly strong for repeated transposons at a euchromatic site near heterochromatin, but also results from repeats at a site distant from heterochromatin. Inactivation strengthens with increasing copy number. The variegated phenotypes are subject to the effects of genetic modifiers of PEV.

Degree of pigmentation varies from very pale yellow to dark red, depending on genomic site of insertion.

When introduced into w- flies the eye colour can vary from pale yellow to red depending on site of integration.

External Data
Show genetic interaction network for Enhancers & Suppressors
Phenotypic Class
Enhanced by

w+mC has abnormal eye color phenotype, enhanceable by Taf91

Suppressor of

w+mC is a suppressor of abnormal eye color phenotype of g50e

Phenotype Manifest In
Enhanced by

w+mC has pigment cell phenotype, enhanceable by Taf91

w+mC has phenotype, enhanceable by Wowγb

w+mC has phenotype, enhanceable by Wowγe

w+mC has phenotype, enhanceable by Wowems1

w+mC has phenotype, enhanceable by Wowhd1

NOT Enhanced by

w+mC has phenotype, non-enhanceable by Low1

NOT suppressed by

w+mC has phenotype, non-suppressible by Low1

Suppressor of

w+mC is a suppressor of pigment cell phenotype of g50e

Additional Comments
Genetic Interactions

Transfection of w+mC is capable of increasing the amount of pigment in the eyes of we(g), g2/Y mutant flies, depending on the level of its expression. Strong expression of w+mC is capable of restoring pigment to g2/Y single mutant levels, thus rescuing the we(g) effect. One copy of the w+mC transgene is sufficient to increase the amount of red pigment in the eyes of both male and female w+, g50e flies.

The eye pigmentation of flies carrying w+mC in a w1118 flies is reduced by e(y)11 in a number of different P{CaSpeR-3} insertion strains.

The eye colour of flies carrying w+mC on the X chromosome is unaffected by a single copy of Low1.

Xenogenetic Interactions
Complementation and Rescue Data
Partially rescues

w+mC partially rescues w1118

w+mC partially rescues w1


w+mC rescues the low courtship vigor index seen in daylight in w1118 males in response to a receptive virgin female.

w1118 males rescued with w+mC court decapitated virgin females vigorously, independent of light conditions.

The reduced sexual discrimination of w1118 males in the dark (they show similar courtship levels towards decapitated males and decapitated females) is not rescued by w+mC.

In daylight, w1118 males rescued by w+mC show a clear courtship preference for decapitated females over decapitated males, although the level of courtship towards decapitated males shown by the rescued males is higher than the level seen in Oregon-R males under these conditions.

Groups of naive w1118 males rescued by w+mC show chaining behaviour under daylight conditions. This behaviour can be rescued by Dp(1;Y)w+y+.

One copy of w+mC restores courtship disinhibition after repeated ethanol exposure (observed as intermale courtship) in w1118 males.

Transfection of w+mC into w1 mutant flies increases pigment levels in the eye from <1% to between 21 and 97%, depending on the insertion of the w+mC construct.

Images (0)
Stocks (16)
Notes on Origin

Transgene expresses subnormal amounts of eye pigment.

Used as a reporter in experiments with a chromatin insulator from the chicken Β-globin domain.

Carried in cosmid vector cosP{cosPer}.

129 different lines carrying P{CaSpeR} have been generated by transformation, in order to investigate the effect of location of the P{CaSpeR} element, gene dosage and sex of the transformed flies on w+mC expression. lzb suppresses the expression of w+mC, the degree of suppression depending on the location and dosage of w+mC.

Shows greater (full) dosage compensation in X chromosomal than in autosomal sites.

The w+mC allele has been used as a semidominant marker in the introgression of marked segments of D.mauritiana chromosomes into D.simulans.

Carried in plasmids "P{hs-per}" and "P{hs-tim-GFP}".

Ufo1 suppresses w eye phenotype.

External Crossreferences and Linkouts ( 10 )
GenBank Nucleotide - A collection of sequences from several sources, including GenBank, RefSeq, TPA, and PDB.
Synonyms and Secondary IDs (5)
Reported As
Symbol Synonym
Name Synonyms
Secondary FlyBase IDs
  • FBal0046767
References (2,614)