asp^L1/asp^E3 transheterozygous adults exhibit a smaller brain, due to smaller central brain and optic lobe, as compared to controls.

Transheterozygous asp^E3/asp^L1 pharates present a striking reduction of the head size while abdomen and thorax seem unaffected.

Unlike wild-type, asp^E3/asp^L1 mutant spermatocytes at late prophase are still located at the plasma membrane, where they remain throughout meiosis. The microtubule organising centres (MTOCs) are found at the periphery of mutant spermatocytes, unlike in controls where the MTOCs are seen near the nuclear membrane. Microtubule organisation is significantly different to wild-type in mutant spermatocytes. At the time of nuclear envelope breakdown (NEB), a distinct focus of microtubule polymerisation appears within the nuclear region, away from the asters. It gives rise to a few bundles that grow and get organised into a bipolar spindle-shaped microtubule array that in 28% of cells is anastral and establishes no contact with the membrane-bound centrosomes. The remainder are accounted for by cell in which, despite the distance, microtubules from one or both asters reach the spindle so that spindle poles and asters are aligned. The timing of meiosis progression from nuclear envelope breakdown (NEB) to anaphase onset seems to be largely unaffected. Chromosome segregation is abnormal in these cells. During prometaphase, the bivalents do not move to the extent that they do in control cells. Congression occurs, but orientation is rarely bipolar. Homologue chromosomes separate at the onset of anaphase, but they barely move, remaining near the centre of the spindle. Moreover they tend to cosegregate and end up included in the same daughter nucleus. Cytokinesis does proceed to completion in around half of mutant cells. These cells contain unconnected centrosomal asters and anastral spindles. These anastral spindles can be observed at any angle, even 90^oC with respect to the position of the two asters. In most such cases, furrow progression forces the spindle to rotate and align with asters so that at the end, a fairly normal cytokinesis takes place. The orientation of the plane of cleavage keeps a tight 90+-10^o with respect to the axis defined by the asters and does not correlate with the orientation of the anastral spindle.

Unfertilized eggs have either no nuclei or a small number of large nuclei, free centrosomes and independent arrays of microtubules. Fertilized eggs from homozygous asp females have this phenotype and embryos that undergo varying degrees of aberrant morphogenesis. The embryos have free centrosomes, abnormal arrays of microtubules and have large areas that are devoid of or have a reduced number of nuclei. Brain neuroblasts of homozygous asp larvae have a high mitotic index and have condensed chromosomes as if blocked at metaphase. Immunostaining reveals that many cells have a single centrosome connected to the metaphase chromosomes by microtubules connected in a hemi-spindle-like structure.