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General Information
D. melanogaster
FlyBase ID
Feature type
Associated gene
Associated Insertion(s)
Carried in Construct
Also Known As
spn-C094, spnC094
Key Links
Nature of the Allele
Mutations Mapped to the Genome
Additional Notes
Nucleotide change:


Reported nucleotide change:


Amino acid change:

G637E | mus301-PA

Reported amino acid change:



The reported amino acid change is an apparent typographical error. Changing G to A at the reported nucleotide location results in a Gly to Glu mutation, rather than Gly to Gln. The A of the initiator ATG was used used as the +1 nucleotide.

Associated Sequence Data
DNA sequence
Protein sequence
Progenitor genotype
Nature of the lesion

Nucleotide substitution: G2101A.

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

100% of mus301094/Df(3L)66C-G28 egg chambers have a mutant karyosome and 2% have misplaced oocytes. 49% of eggs laid by mus301094/Df(3L)66C-G28 females are ventralised.

100% of mus301094/mus301D1 egg chambers have a mutant karyosome and 2% have misplaced oocytes. 21% of eggs laid by mus301094/mus301D1 females are ventralised.

mus301094/Df(3L)66C-G28 females show 17% X chromosome nondisjunction. mus301094/Df(3L)ZP3 females show 15% X chromosome nondisjunction.

mus301094/Df(3L)66C-G28, mus301094/mus301660, mus301094/mus301D1, mus301094/mus301D2 and mus301094/mus301D4 larvae are sensitive to MMS compared to controls.

mus301094 animals do not survive exposure to 0.08% methyl methanesulfonate.

26% of eggs laid by homozygous females have wild-type dorsal appendages, 50% have fused dorsal appendages and 24% have no dorsal appendages.

In contrast to wild-type ovaries, where the synaptonemal complex (SC) is always restricted to the oocyte by region 2b, mus301094 mutant females show a significant delay in the process, with cysts with more than 1 cell in synapsis in region 3 of the germarium and in stage 1 and stage 2 of the vitellarium. Cysts with 4 cells in meiosis are often found in region 2b of the germarium.

The oocyte is not correctly positioned in 32% of cysts in homozygous females.

Eggs exhibit a strong ventralised phenotype: eggs are longer than wild type and are completely symmetric along the DV axis. Egg chambers of females exhibit a partially penetrant disruption in the positioning of the oocyte which can be located anywhere in the egg chamber. Almost all oocytes lack a karyosome and the oocyte chromosomes are arranged instead in thread-like figures with irregular shape. Germline clones in egg chambers are composed of wild type follicle cells, mutant nurse cells, misplaced oocyte, oocytes that give rise to ventralised eggs and oocytes that lack a karyosome.

In approximately 60% of mutant egg chambers, the oocyte fails to move to the posterior and lies either at the anterior of the germline cyst or in the middle, with nurse cells on both sides. Follicle cells migrate to the middle of the bipolar egg chamber, to form a belt around the oocyte. Germline clones show the same mutant phenotype.

Posterior localization of vas protein.

maternal-effect lethal Egg shape affected; in extreme cases dorsal appendages are lacking and eggs have little or no dorsal-ventral polarity; some eggs have one fused dorsal appendage. Low fecundity; eggs often slightly collapsed.

External Data
Show genetic interaction network for Enhancers & Suppressors
Phenotypic Class
Phenotype Manifest In
Additional Comments
Genetic Interactions

mei-41D3/mei-41RT1 partially suppresses the dorsal appendage defects of mus301094 homozygotes; 70% of eggs derived from double mutant females have wild-type dorsal appendages, 21% have fused dorsal appendages and 9% have no dorsal appendages. The dorsal appendage defects of eggs derived from mus301094 females are not suppressed by Df(2L)be408 P{CG10728+tMa}/Df(2L)pr2b P{barr+tMa}.

The eggshell patterning defects of eggs derived from mus301D4/mus301094 females are suppressed if the females also carry mei-W68unspecified/Df(2R)LL5, mei-41D3/+ or mei-41D3/mei-41D3.

Double mutant stage 5-6 egg chambers with spn-A3, spn-B1 or spn-E1 exhibit a two-oocyte phenotype: the second pro-oocyte develops as an oocyte rather than a nurse cell. The double mutants delay but do not block the decision between the two pro-oocytes as one of the two cells always becomes a nurse cell eventually.

Xenogenetic Interactions
Complementation and Rescue Data
Images (0)
Stocks (0)
Notes on Origin
External Crossreferences and Linkouts ( 0 )
Synonyms and Secondary IDs (4)
References (10)