Open Close
General Information
D. melanogaster
FlyBase ID
Feature type
Associated gene
Associated Insertion(s)
Carried in Construct
Also Known As
Nature of the Allele
Mutations Mapped to the Genome
Additional Notes
Associated Sequence Data
DNA sequence
Protein sequence
Progenitor genotype
Nature of the lesion

Deletion of the entire coding region.

Approximately 1kb deletion in the 0 to -2kb region.

results from about 1 kb deletions which remove most or all of the tra locus.

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 )
Phenotypic Data
Phenotypic Class
Phenotype Manifest In
Detailed Description

Under control conditions, tra1 adult posterior midgut clones are significantly smaller in females only, as compared to control clones.

Under control conditions, traKO.Cherry/tra1 transheterozygotes and traKO.Cherry/tra1 transheterozygotes that also express traUAS.cFa under the control of Scer\GAL4esg-NP7397 during adulthood do not show significant changes in the adult posterior midgut mitotic index in females, as compared to controls.

The pseudo-testes of XX tra1/Df(3L)st-j7 animals are atrophic.

tra1/Df(3L)st-j7 XX animals have a complete transformation in their brain neuropil morphology to that normally seen males. There is no difference in the size of the the "male-enlarged region" (MER) in the brains of tra1/Df(3L)st-j7 XX and XY animals compared to control males.

Homozygous tra1 XX animals show hight rates of courtship behaviour, comparable to those shown by wild-type males.

P1 neurons are formed in the brains of both XX and XY tra1 homozygotes (these neurons are normally only found in male brains in the wild type).

tra1 mutant females develop `male' specific serotonergic neurons in an identical pattern as in wild-type males.

tra1/Df(3L)st-j7 mutant gonads are masculinised with regard to hub formation (germline stem cell niche formation).

In mutant females "neurons medially located, just above antennal lobe" (mALs) persist and have male-like bilateral projections.

Male-specific somatic gonadal precursors appear to be present in the posterior somatic gonad of both male and female stage 15 tra1 mutants in a manner comparable to wild-type males. These precursors are not present in wild-type females.

Chromosomal females homozygous for tra1 differentiate as males.

XX tra1/tra4 animals develop as pseudomales. Three categories of gonad are seen. Approximately 50% of pseudomales have 'atrophic' gonads, which contain no differentiating germ cells (spectrosomes, fusomes and ring canals are not seen). The remainder of gonads contain germ cells which initiate gametogenic differentiation (spectrosomes and fusomes are seen). 19% of these gonads are 'non-oogenic', and in most of these cases the germ cells are connected by multibranched fusomes containing actin (a spermatogenic characteristic). The remaining 33% of gonads are 'oogenic'.

The histological structures of the terminal segment of homozygous females are studied: some internal organisation and muscles patterns are male like. Homozygous males show no significant changes in the internal organisation of the terminal segment.

Heat induced expression in X/X tra1/tra1 trahs.PBa and X/Y tra1/tra1 trahs.PBa mutants during the temperature-sensitive period (shortly before puparium formation and into early metamorphosis) abolishes male behaviour. These mutants exhibit a female body (except for the CNS) and have a female pheromone pattern. They show indiscriminate mating behaviour, suggesting they are unable to discriminate among their sexual partners (these 'females' will mate with M.domestica males). X/X tra1/tra1 trahs.PBa females are fertile. Heat induced expression during the temperature-sensitive period abolishes male behaviour and allows partial recovery of female behaviour in the X/X mutants, the X/Y mutants show some female behaviour. Heat induced expression before and after, but not during, the temperature-sensitive period in X/X mutants does not abolish male behaviour. Irrespective of the heat-shock regimen all flies have a female pattern of pheromones. By introducing dsxD, X/X and X/Y flies now have a male body and male pheromone pattern, these flies are unattractive to males but will still court both sexes.

Heterozygous females are fertile, heat induced expression of trahs.PBa does not affect fertility. When mated females exhibit normal sperm storage. Homozygous females are 'female' with a male CNS, exhibit male behavior and are sterile, heat induced expression of trahs.PBa restores female behaviour and fertility. Mated females exhibit abnormal sperm transport. Homozygous males are 'female' with a male CNS, exhibit male behavior and are sterile, heat induced expression of trahs.PBa allows a female sexual phenotype, female behaviour but flies are sterile. Mated 'females' exhibit abnormal sperm transport.

The gonads of XX hemizygotes contain many small undifferentiated germ cells.

Less than half of XX tra1/tra4 mutant pseudomales produce gonads with the most severe group 1 pseudotestes phenotype. The remaining pseudomales have a less severe phenotype, with viable germ cells. otu10 and Df(1)otu-PΔ1 cause an increase in severity of this phenotype: over 70% of the resulting gonads were of group 1. An increase in otu activity in XX otuhs.PN, tra1/tra4 leads to elongated pseudotestes categorized as having a group 3 phenotype.

X/X; tra1/tra1 gonads of first instar larvae are mostly male-like in size and morphology. Some germ cells degenerate while others appear spermatogenic.

30% of XX and 56% of XY dsx1 tra1 double homozygous flies show male-specific courtship when paired with mature virgin females.

Males can transfer sperm to females when mating.

Females exhibit segment spanning muscles in the fifth abdominal segment indicative of a transformation to the male specific phenotype. Somatic development of males is unaffected.

Transforms females to normal-appearing males (sex-combs, normal external and internal male genitalia, normal courtship and mating). Testes are very small, but are of normal colour and shape.

External Data
Show genetic interaction network for Enhancers & Suppressors
Phenotypic Class
NOT Enhanced by
NOT Enhancer of
Suppressor of

tra1 is a suppressor of lethal | dominant | male limited phenotype of SxlM6

Phenotype Manifest In
Additional Comments
Genetic Interactions

Expression of Phf7EY03023 under the control of Scer\GAL4nos.UTR.T:Hsim\VP16 rescues the size and morphology of 6% of the gonads of XX tra1/Df(3L)st-j7 animals to a wild-type looking pseudo-testis. These rescued pseudo-testes contain late-stage sperm, including sperm tails and condensed chromatin.

The addition of up to three copies of P{snf+,dhd+} to Sxlf1/Y;SxlF1.hs, tra1 partially feminised males does not enhance the feminisation or lethality phenotypes seen in these flies. The addition of snf1 completely suppresses the male-specific lethality seen in SxlM6/Y males. If the snf does is increased by the addition of one or more copies of P{snf+,dhd+}, the lethality returns.

XX tra1/tra4 pseudomales that are also homozygous for ovoD1rv23 show an increase in the frequency of atrophic gonads compared to XX tra1/tra4 pseudomales. Non-oogenic gonads, with spectrosomes and multibranched fusomes are also seen (at the same frequency as XX tra1/tra4 pseudomales). XX tra1/tra4 pseudomales that are also homozygous for Df(1)otu-PΔ1 show an increase in the frequency of atrophic gonads and a decrease in the frequency of oogenic gonads compared to XX tra1/tra4 pseudomales. Non-oogenic gonads, with spectrosomes and multibranched fusomes are seen at the same frequency as XX tra1/tra4 pseudomales. XX tra1/tra4 pseudomales that are also homozygous for Sxlf5 show a decrease in the frequency of oogenic gonads and an increase in the frequency of non-oogenic gonads compared to XX tra1/tra4 pseudomales. Atrophic gonads are seen at the same frequency as XX tra1/tra4 pseudomales. XX tra1/tra4 pseudomales that are also carrying otuhs.PN and raised at 20-25oC are 2 to 3 times longer than normal. Expression of otuhs.PN partially rescues XX tra1/tra4 pseudomales; 88% of the gonads are 'feminised' and show a developmental progression of gametogenic stages, which can be divided into three sections corresponding to germarial regions 1-3 in normal oogenesis. Section I includes the most apical portion of the pseudomale testis and contains gametogenic stages characteristic of germarial region 1 in ovaries. A group of cells containing spectrosomes is localised at the distal tip. Clusters of cells connected by branched fusomes are located immediately adjacent to the distal cells. The fusomes have disappeared in section II and differentiation of the ring canals continues. In section II, the pseudomale germ cells have differentiated to postgermarial stages. The germ cell clusters contain thick ring canals and the nuclei are large. Oogenic gonads are not seen in XX tra1/tra4 pseudomales carrying otuhs.PN that are also homozygous for ovoD1rv23 or Sxlf5. In each case the frequency of non-oogenic gonads is increased compared to XX tra1/tra4 pseudomales also homozygous for ovoD1rv23 or Sxlf5 respectively. Almost 90% of gonads are oogenic in newly eclosed XX tra1/tra4 pseudomales that are also carrying otu104.H. The level of feminisation is markedly reduced 7-10 days after eclosion. The feminisation of XX tra1/tra4 gonads by otu104.H is blocked if they are also carrying Df(1)otu-PΔ1.

fru1 tra1 double mutants have an abnormal Muscle of Lawrence, like that of fru1 males, males also chain vigorously.

Xenogenetic Interactions
Complementation and Rescue Data
Partially rescued by

tra1 is partially rescued by traF.Hsp83

tra1 is partially rescued by traRB


traF.Hsp83 is able to feminise the soma of tra1 chromosomal females and at least partially restores fertility without heat shock.

Images (0)
Stocks (4)
Notes on Origin


A.H. Sturtevant.


Homozygous XX flies have no Yp1, Yp2 or Yp3 proteins in the haemolymph. Heterozygous flies also homozygous for tra2OTF have a trace of these proteins in the haemolymph.

External Crossreferences and Linkouts ( 0 )
Synonyms and Secondary IDs (2)
References (48)