Mks1^Δ1 mutants are viable and fertile and show no defects in coordination or developmental timing and the male fertility is comparable to wild-type. The adult flies perform normally in the climbing assay but climb slightly faster than controls and display a subtle increase in head grooming. Adult Mks1^Δ1 mutants also do not display any defects in the electrophysiological response of mechanosensory bristles in the notum, in fact the mechanical response potential generated upon mechanical stimulation of these bristles is slightly higher than in controls but still falls within the normal range.

No dramatic structural defects are observed in the sperm flagella in Mks1^Δ1 mutant males but the short axonemes normally assembled in mature spermatocytes are much shorter than in controls. At 48 hr after puparium formation (APF), the sensory cilia of Mks1^Δ1 mutants are thinner compared to controls as most of the basal body microtubules terminate just above the transition zone and the crystalline-like structure at the tip of the axoneme is also disorganized. The arrangement of the centriole pairs and ciliary rootlets at the base of the cilium is largely unperturbed. Interestingly, at 72 hr APF, the structure of the Mks1^Δ1 mutant cilia is much more similar to wild-type, although there is a larger volume of inner membrane in the mutants.