Markers / Condition
Which genes affect sleep and whether you are a morning person?
Your body clock evolved under a bright day and a dark night, and now runs under neither. The genetics of chronotype is real but heavily polygenic, and light exposure moves it far more than any variant does.
The markers
Morning or evening person
rs1801260 · CLOCK
CLOCK is a core gene of the circadian machinery that keeps your body on a roughly 24-hour cycle. The variant version is associated with going to bed later and preferring evenings. In an environment of electric light and indoor work, a late clock stops being a preference and becomes a mismatch.
Two copies: You have the later-clock version on both copies
How deeply you sleep
rs73598374 · ADA
Adenosine is the molecule that builds up while you are awake and makes you feel sleepy, and it is what caffeine blocks. This variant slows the enzyme that breaks adenosine down, so sleep pressure builds higher, and carriers show measurably more deep slow-wave sleep.
Two copies: You have the slower enzyme on both copies
How fast you clear caffeine
rs762551 · CYP1A2
CYP1A2 does about ninety-five per cent of the work of breaking caffeine down. This position marks the faster and slower versions of the enzyme.
Two copies: Slow metaboliser
Which versions do you carry?
All of these are readable from an ordinary home DNA test file, in your browser, without uploading it anywhere.
Read my fileCommon questions
Which genes affect sleep and whether you are a morning person?
Your body clock evolved under a bright day and a dark night, and now runs under neither. The genetics of chronotype is real but heavily polygenic, and light exposure moves it far more than any variant does. The markers most often cited are rs1801260 in CLOCK, rs73598374 in ADA, rs762551 in CYP1A2.
What does rs1801260 do?
CLOCK is a core gene of the circadian machinery that keeps your body on a roughly 24-hour cycle. The variant version is associated with going to bed later and preferring evenings. In an environment of electric light and indoor work, a late clock stops being a preference and becomes a mismatch. Carrying two copies: you have the later-clock version on both copies.
What does rs73598374 do?
Adenosine is the molecule that builds up while you are awake and makes you feel sleepy, and it is what caffeine blocks. This variant slows the enzyme that breaks adenosine down, so sleep pressure builds higher, and carriers show measurably more deep slow-wave sleep. Carrying two copies: you have the slower enzyme on both copies.
What does rs762551 do?
CYP1A2 does about ninety-five per cent of the work of breaking caffeine down. This position marks the faster and slower versions of the enzyme. Carrying two copies: slow metaboliser.
Reference information, not medical advice and not a diagnosis. See the medical disclaimer.