. 2013 May;143(5):1489–1499. doi: 10.1378/chest.12-1219

Table 1.

—Mammalian Genes That Influence Circadian Rhythm and Their Close Counterparts in the Drosophila melanogaster Fruit Fly

Mammalian Gene	Drosophila Gene
Clock (CLOCK^a)	Clock
Period 1, 2, and 3 (PER1,^a PER2,^a and PER3^a)	Period
Cryptochrome 1 and 2 (CRY1^a and CRY2^a)	Cryptochrome
BMAL1 (ARNTL^a)	Cycle
Timeless (TIMELESS^a)	Timeless
CK1δ and CK1ε (CSNK1E^a)	Doubletime

Adapted with permission from Allada.⁸⁵

Currently approved gene symbol per the Human Genome Organisation International Gene Nomenclature Committee database.⁸⁴