period homolog 1 (Drosophila)
Identifiers
Symbol	PER1
Alt. symbols	PER
Entrez	5187
HUGO	8845
OMIM	602260
RefSeq	NM_002616
UniProt	O15534
Other data
Locus	Chr. 17 p12

period homolog 2 (Drosophila)
Identifiers
Symbol	PER2
Entrez	8864
HUGO	8846
OMIM	603426
RefSeq	NM_003894
UniProt	O15055
Other data
Locus	Chr. 2 q37.3

period homolog 3 (Drosophila)
Identifiers
Symbol	PER3
Entrez	8863
HUGO	8847
OMIM	603427
RefSeq	NM_016831
UniProt	P56645
Other data
Locus	Chr. 1 p36.23

Period (per) is a gene in Drosophila which encodes a protein, PER, regulating circadian rhythm. There are some known alleles of the per gene that can make the circadian cycle longer or shorter than the usual cycle (which is around 24 hours). It is still uncertain how exactly this gene operates.

In humans, there are three known PER family genes: PER1, PER2, and PER3.

[edit] See also

• Clock gene
• Suprachiasmatic nucleus
• Timeless (gene)
• Oscillating gene

[edit] External links

• MeSH PER1+protein,+human
• MeSH PER2+protein,+human
• MeSH PER3+protein,+human

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