Homozygous females show a high frequency (more than 50%) of region 3 cysts with two pro-oocytes (as assayed by c(3)G staining) compared to a frequency of only 9.5% in wild type.
In spn-D2 oocytes, both the anterior and later posterior microtubule-organizing centers are much less prominent than in wild-type oocytes.
Over half of spn-D2 eggs show a fused dorsal appendage phenotype and 11% of eggs have no dorsal appendages at all.
spn-D2/spn-D2 females exhibit low fertility, and meioses show reduced frequency of crossing over along most of chromosome 2, but not in the centromeric regions, as compared to wild type.
spn-D2/spn-D1 females exhibit low fertility, and meioses show reduced frequency of crossing over along most of chromosome 2, as compared to wild type.
43% of eggs derived from homozygous females have wild-type eggshells, 57% have mutant eggshells, with 21% having dorsalised eggs with dorsal appendage material around the lateral and ventral side of the egg. 70% of eggs derived from spn-D1/spn-D2 females have mutant eggshells and defects in karyosome morphology are seen in the mutant egg chambers.
In contrast to wild-type ovaries, where the synaptonemal complex (SC) is always restricted to the oocyte by region 2b, spn-D2 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 one cell in synapsis in stage 2 of the vitellarium.
Hemizygotes are viable. spn-D1/spn-D2 larvae show normal sensitivity to methyl methanesulfonate. Recombination frequency is 10-25% of normal levels in homozygous females, and X chromosome non-disjunction is increased 100-fold compared to wild-type.
Hemizygous eggs exhibit either a strong or weak ventralised phenotype: eggs are longer than wild type and are completely symmetric along the DV axis or the eggs display fused dorsal appendages. Egg chambers of females exhibit a partially penetrant disruption in the positioning of the oocyte which can be located anywhere in the egg chamber. 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.