title: The disconnected visual system mutations in Drosophila melanogaster drastically disrupt circadian rhythms.
abstract: Mutations at the disconnected (disco) locus in Drosophila melanogaster cause cultures of this insect to eclose in an essentially arrhythmic manner and also nearly eliminate free-running circadian rhythms of locomotor activity. Yet disco mutants are not totally light-insensitive: Whereas they performed very poorly in tests of certain behavioral responses to visual stimuli, they were able to exhibit "forced" periodic locomotor activity under conditions of light-dark cycling. We discuss these results in the context of (1) the dispensability of this insect's external photoreceptors for entrainment of its circadian pacemaker, and (2) possible disco-induced abnormalities in the connections of extraocular photoreceptors to their targets in the central nervous system and/or abnormalities in the targets themselves--which presumably include elements of the fly's circadian clock.
authors.affiliation: Department of Biology, Brandeis University, Waltham, Massachusetts 02254.
authors.forename: M S
authors.initials: MS
authors.lastname: Dushay
authors.forename: M
authors.initials: M
authors.lastname: Rosbash
authors.forename: J C
authors.initials: JC
authors.lastname: Hall
mesh_terms: D000818:Animals; D002940:Circadian Rhythm; D004331:Drosophila melanogaster / Q000235:genetics*; D008027:Light; D009043:Motor Activity / Q000502:physiology / Q000528:radiation effects; D009154:Mutation; D011680:Pupil; D014785:Vision, Ocular / Q000502:physiology; D014795:Visual Pathways / Q000502:physiology*