rs228697
A SNP in the PER3 gene on chromosome 1. Its most notable genotype is C;G: Somewhat more likely to prefer staying up late
- Gene
- PER3
- Location
- Chr 17,827,519 (GRCh38)
- Highest magnitude
- 2.0Worth knowing
- Tested on
- 23andMe, AncestryDNA
Genotypes
As shown in 23andMe and AncestryDNA files.
- C;CGoodcommon/normal
- C;GMost notableNot ratedSomewhat more likely to prefer staying up late
- G;GNot ratedSomewhat more likely to prefer staying up late
On SNPedia: (C;C), (C;G), (G;G). Magnitude rates how notable a genotype is from 0 to 10, not how risky it is.
Frequency
Share of each genotype in 4 HapMap populations.
- AverageC;C 89% C;G 11% G;G 0%
- European ancestry (Utah)C;C 88% C;G 12% G;G 0%
- Han Chinese (Beijing)C;C 91% C;G 9% G;G 0%
- Japanese (Tokyo)C;C 77% C;G 23% G;G 0%
- Yoruba (Nigeria)C;C 100% C;G 0% G;G 0%
Related
Notes
From SNPedia
Show notes, about 140 words
Based on a study of 182 DSPT individuals, 67 free-running type (FRT) individuals, and 925 controls, all of whom were Japanese and between the ages of 20-40, a 2014 study concluded that rs228697(C;C) individuals were more likely to be "morning types" than "evening types", while rs228697(G) carriers were more common in evening types than in morning types (OR: 2.483; CI: 1.339–4.603, Bonferroni-corrected p = 0.012; crude p = 0.004). Similarly, the frequency of the G allele for rs228697 was significantly increased in FRT individuals compared with controls (OR: 2.021; CI: 1.160–3.524; permutated p = 0.017; crude p = 0.011).
C;G
Somewhat (~2x) more likely to prefer staying up late compared to rs228697(C;C) individuals; see rs228697 for details.
G;G
Somewhat (~2x) more likely to prefer staying up late compared to rs228697(C;C) individuals; see rs228697 for details.
Source and license
Adapted from rs228697 on SNPedia, using a snapshot taken October 16, 2026. SNPedia content is shared under CC BY-NC-SA 3.0 US, and this page is shared under the same license.
SNPedia is a community-edited wiki. Its entries can be incomplete, out of date or wrong, and nothing here is a diagnosis or medical advice. Magnitude is a community rating of how interesting a genotype is, not a risk score.