The 50th anniversary of the Konopka and Benzer 1971 paper in PNAS: 'Clock Mutants of Drosophila melanogaster'

On September 1, 1971, unknowingly to most, the world changed for the fields of behavioral genetics and circadian clocks. Ronald Konopka, a graduate student with Seymour Benzer at Caltech, published a paper (1) that I would argue is the most important discovery ultimately leading to our current molecular understanding of the circadian clock in animals. In this classic paper, Ron and Seymour reported the isolation of three single-gene mutants in Drosophila that dramatically altered circadian rhythms in pupal eclosion and locomotor activity. One mutant exhibited no rhythmicity, another had a short 19-h period, and a third had a long 28-h period. Remarkably, all three mutants mapped to the same locus on the X chromosome. They named this gene period . Seymour Benzer had recently joined the faculty at Caltech in 1967, after two previously successful careers in physics and molecular biology, and spurred on by Max Delbruck to do something more interesting, launched his third career in behavioral biology (2⇓⇓–5). Having done a sabbatical at Caltech with Roger Sperry, Seymour interacted with Ed Lewis, a giant in Drosophila genetics who trained with Alfred Sturtevant (descendent of Thomas Hunt Morgan) (6). Seymour chose Drosophila as a model system because its nervous system was intermediate in complexity “between a single neuron and the human brain” yet exhibited complex behavior and was amenable to genetic analysis (7). That same year, Seymour published his first paper (8) using mutagenesis and countercurrent technology to isolate phototaxis mutants in Drosophila . The opening sentence of this paper reads, “Complex as it is, much of the vast network of cellular functions has been successfully dissected, on a microscopic scale, by the use … [↵][1]1Email: joseph.takahashi{at}utsouthwestern.edu. [1]: #xref-corresp-1-1