Onion-stage spermatids in Grip75¹⁷⁵/Df(2L)ED8142 transheterozygotes show a significant increase in nuclear volume.

Mutant third larval instar brain neuroblasts take much longer to establish a metaphase plate during division than wild-type neuroblasts, and the microtubules appear to have difficulty in capturing and aligning the chromosomes. The metaphase spindle is abnormal; the kinetochore fibres do not appear to be reinforced by the formation of additional microtubules within the spindle and microtubule density within the spindle remains low. The spindle structure is unstable, often flexing and bending, and is longer than normal. The mutant cells are delayed in exiting mitosis, but eventually undergo a normal asymmetric division.

Grip75¹⁷⁵ mutant adults of both sexes exhibit a slight increase in lethality some days after hatching. They exhibit abnormalities in the abdominal cuticle segmentation and the thoracic macrochaete pattern. Mutant females are sterile due to a failure to undergo normal oogenesis.

Grip75¹⁷⁵ mutant L3 larval brains exhibit a three-to fourfold elevation in mitotic index compared with wild-type cells. Mutant cells accumulate in prometaphase stages, wereas postmetaphase figures are reduced. More than half of the mutant cells exhibit overcondensed chromosomes, consistent with prolonged prometaphase and metaphase stages. However, only very few mutant cells show an aneuploid phenotype compared to wild-type, consistent with Grip75¹⁷⁵ adult viability.

Spindle formation in meiosis I appears normal in homozygous oocytes. In homozygous eggs, the first meiotic spindle is anastral (as in wild type) and appears to function properly. However, meiosis II is severely disrupted in these eggs; the central array of microtubules is absent, and instead two anastral spindles are formed, which are not properly aligned to each other and to the cortex, or the spindles are strongly disorganised.

At the onion stage, mutant spermatids often have a Nebenkern that is twice the size of a regular Nebenkern and which is associated with two nuclei. Spermatids often have flagella with two axonemes and the nuclei are dispersed along the entire sperm bundle (in contrast to wild type, where the nuclei are packed at one end of the sperm bundle). The microtubule arrangements of the mutant axonemes are normal.

Grip75¹⁷⁵ germ-line clone derived eggs arrest early in development, as judged by a lack of cuticle development.