Both wild-type and asl mutant brain neuroblasts divide asymmetrically. Mutant larval neuroblasts are defective in centrosome structure and fail to nucleate astral microtubules, leading to the formation of anastral spindles that are built around the chromatin. The anastral neuroblast spindles are well focused and are able to mediate cell division correctly. Mutant spermatocytes are defective in centrosome structure and fail to nucleate astral microtubules, leading to the formation of anastral spindles that are built around the chromatin. The meiotic spindles are very poorly focused; chromosomes fail to align on the metaphase plate and often missegregate.

Homozygous primary spermatocytes develop a peculiar anastral spindle, despite lacking asters. Microtubules grow from multiple sites near the chromosomes and form radial arrays extending from each bivalent. These microtubules organise into bipolar bundles, creating minispindles associated with individual bivalents, although not all bivalents develop clear minispindles (some remain associated with a nonpolarised or poorly polarised network of microtubules). The bundles of microtubules associated with bivalents are often oriented in different directions. The meiotic chromosomes progress into a highly irregular anaphase A. The homologues manage to segregate, but their separation is often asynchronous. Anaphase I chromosomes are not organised into two discrete sets, but are scattered throughout the cell. After anaphase A, the cells undergo anaphase B. Approximately 85% of cells develop a central spindle which is indistinguishable from wild-type. The remaining cells form tripartite or multipartite central spindles. The central spindle is asymmetrically localised in approximately 80% of those cells with normal central spindles. Approximately 70% of telophase I figures show unequal chromosome segregation.