Markers / Condition
Which genes control skin colour, hair colour and how you burn?
Pigmentation is the best understood complex human trait there is, and the clearest case of the environment shaping a body part. Skin lightened as populations moved away from the tropics, where strong sun would otherwise destroy folate, into places where weak sun made vitamin D hard to come by. Europe and East Asia did it with different genes.
The markers
| Marker | Gene | What it does | Evidence |
|---|---|---|---|
| rs1426654 | SLC24A5 | One of the biggest switches for skin tone | established |
| rs28777 | SLC45A2 | The second big pigmentation switch | established |
| rs12913832 | HERC2 | Eye colour | established |
| rs1800414 | OCA2 | Lighter skin, the East Asian route | established |
| rs6058017 | ASIP | The pigment switch that works in the opposite direction | strong |
| rs12203592 | IRF4 | Freckles, and hair that darkens with age | established |
| rs1393350 | TYR | Freckling and sun sensitivity, second marker | strong |
| rs1805007 | MC1R | Red hair variant R151C | established |
| rs1805008 | MC1R | Red hair variant R160W | established |
| rs3827760 | EDAR | Hair thickness and shovel-shaped front teeth | established |
One of the biggest switches for skin tone
rs1426654 · SLC24A5
A single letter change in SLC24A5 accounts for a large share of the difference in skin pigmentation between European and West African populations. It is one of the strongest single-gene effects on any visible human trait, and it swept through Europe in the last ten thousand years.
Two copies: Lighter skin version, two copies
The second big pigmentation switch
rs28777 · SLC45A2
SLC45A2 sits alongside SLC24A5 as one of the two strongest pigmentation genes. Between them they account for much of the difference in skin tone across populations.
Two copies: Lighter-skin version, two copies
Eye colour
rs12913832 · HERC2
A single position in a control region for the pigment gene OCA2 accounts for most of the blue-versus-brown difference in people of European descent. Nearly every blue-eyed person alive carries the same version, inherited from one ancestor.
Two copies: Blue or grey eyes very likely
Lighter skin, the East Asian route
rs1800414 · OCA2
Europe and East Asia both evolved lighter skin after moving away from the tropics, and they did it with different genes. This is the East Asian one. It is a clean demonstration that the same environmental problem was solved twice, independently.
Two copies: You carry two copies
The pigment switch that works in the opposite direction
rs6058017 · ASIP
ASIP tells pigment cells to make the lighter red-yellow pigment instead of the dark brown one. Unlike most pigmentation variants studied in Europeans, this one varies strongly across African and South Asian populations too.
Two copies: You carry two copies
Freckles, and hair that darkens with age
rs12203592 · IRF4
IRF4 helps control pigment production. This change is one of the strongest known predictors of childhood freckling, and it is also linked to hair that starts fair and darkens through childhood.
Two copies: Freckling most likely
Freckling and sun sensitivity, second marker
rs1393350 · TYR
TYR makes the enzyme at the very start of pigment production. This change is linked to freckling, fairer skin and a greater tendency to burn.
Two copies: Two copies, so most likely to freckle and to burn rather than tan
Red hair variant R151C
rs1805007 · MC1R
MC1R decides which of the two pigments your skin and hair make. Several partly-broken versions push production towards the red-yellow pigment, and this is the strongest of the common ones.
Two copies: Two copies, so red hair and very fair skin are highly likely
Red hair variant R160W
rs1805008 · MC1R
The second of the common strongly red-associated versions of MC1R.
Two copies: Two copies, so red hair and very fair skin are highly likely
Hair thickness and shovel-shaped front teeth
rs3827760 · EDAR
One change in EDAR thickens hair shafts, increases sweat gland density and puts a distinctive scooped shape on the back of the upper front teeth. It arose in East Asia around thirty thousand years ago and reached very high frequency there.
Two copies: Two copies, so thick hair and shovel-shaped front teeth are likely
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 control skin colour, hair colour and how you burn?
Pigmentation is the best understood complex human trait there is, and the clearest case of the environment shaping a body part. Skin lightened as populations moved away from the tropics, where strong sun would otherwise destroy folate, into places where weak sun made vitamin D hard to come by. Europe and East Asia did it with different genes. The markers most often cited are rs1426654 in SLC24A5, rs28777 in SLC45A2, rs12913832 in HERC2, rs1800414 in OCA2, rs6058017 in ASIP.
What does rs1426654 do?
A single letter change in SLC24A5 accounts for a large share of the difference in skin pigmentation between European and West African populations. It is one of the strongest single-gene effects on any visible human trait, and it swept through Europe in the last ten thousand years. Carrying two copies: lighter skin version, two copies.
What does rs28777 do?
SLC45A2 sits alongside SLC24A5 as one of the two strongest pigmentation genes. Between them they account for much of the difference in skin tone across populations. Carrying two copies: lighter-skin version, two copies.
What does rs12913832 do?
A single position in a control region for the pigment gene OCA2 accounts for most of the blue-versus-brown difference in people of European descent. Nearly every blue-eyed person alive carries the same version, inherited from one ancestor. Carrying two copies: blue or grey eyes very likely.
What does rs1800414 do?
Europe and East Asia both evolved lighter skin after moving away from the tropics, and they did it with different genes. This is the East Asian one. It is a clean demonstration that the same environmental problem was solved twice, independently. Carrying two copies: you carry two copies.
Reference information, not medical advice and not a diagnosis. See the medical disclaimer.