Flies homozygous for ken141 undergo embryonic development but fail to hatch, but no defects were observed in the number of neurons or their projections.
ken141/ken1 transheterozygotes display the same adult phenotypes (abnormal, often missing, genitalia; unpigmented aristae; wings held out away from the body) characteristic or viable ken mutants. No obvious morphological defects are seen in the giant fiber neurons.
Homozygous ken1 mutant adults as well as ken1/Df(2R)or-BR11 hemizygotes and ken1/ken141 transheterozygotes show defective light-off escape behavior, phototaxis and general locomotor activity compared to wild-type controls, with the hemizygotes showing the most severe phenotype in all assays.
Both adult ken1 homozygotes and ken141/ken1 transheterozygotes show defects in the electrophysiology of the giant fibre system: they display longer response latencies and a lower percentage following to 10 stimuli at 250Hz in tergo trochantal muscles compared to wild-type controls. When stimulated directly, the muscles of ken1 mutants respond with the correct short latency characteristic for normal neuromuscular junctions.