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Laboratory of Genetics

The First Clock Gene

The genetics of circadian rhythmicity began with Konopka and Benzers discovery of three Drosophila clock mutants in 1971. The mutants produced long-period or short-period behavioral rhythms, or no rhythms at all. Activity/rest cycles and daily patterns of eclosion (emergence of the adult from the puparium) were similarly affected by the mutants. All three mutations mapped to the same X-linked gene. This gene was given the name period (download page).

DNA composing the period gene was first isolated at Rockefeller (download page). This 1984 study identified the period transcription unit and described the effects of a period mutation on transcription of the gene.

The molecular genetics of circadian clocks expanded to Neurospora in 1989 with the cloning of a gene called frequency. In 1997 the first clock genes from mammals were isolated. These included orthologs of period. Today the molecular basis of circadian rhythmicity is followed in bacteria, fungi, plants, and a variety of vertebrates in addition to the fruitfly. So far, period has only been found to play a role in animal clocks.