Sehgal, A., Price, J.L., Man, B., Young, M.W. (1994). Loss of circadian behavioral rhythms and per RNA oscillations in the Drosophila mutant timeless.  Science 263(5153): 1603--1606.

FBrf0068680

Research paper

Eclosion, or emergence of adult flies from the pupa, and locomotor activity of adults occur rhythmically in Drosophila melanogaster, with a circadian period of about 24 hours. Here, a clock mutation, timeless (tim), is described that produces arrhythmia for both behaviors. The effects of tim on behavioral rhythms are likely to involve products of the X chromosome-linked clock gene period (per), because tim alters circadian oscillations of per RNA. Genetic mapping places tim on the left arm of the second chromosome between dumpy (dp) and decapentaplegic (dpp).