rs28777
The second big pigmentation switch
What this position does
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.
What each result means
| If you carry | What it means |
|---|---|
| No copies of the effect version CC | Darker-skin version, two copies Two copies of the higher-pigment version. |
| One copy AC | One of each An intermediate result is typical. |
| Two copies AA | Lighter-skin version, two copies Two copies of the lighter version, carried by the large majority of Europeans. |
How common each version is
| Ancestry group | A (the effect version) | |
|---|---|---|
| African | 19.5% | |
| American | 49.3% | |
| East Asian | 11.7% | |
| European | 95.6% | |
| South Asian | 22.3% |
1000 Genomes Project phase 3, via Ensembl, retrieved 2026-09-23. These groupings are coarse and flatten a great deal of internal diversity, particularly within Africa. A variant being common somewhere tells you where a piece of your ancestry probably comes from, and nothing else.
How many people carry each result
| Ancestry group | CC | AC | AA |
|---|---|---|---|
| African | 434 / 661 | 196 / 661 | 31 / 661 |
| European | 2 / 503 | 40 / 503 | 461 / 503 |
| East Asian | 392 / 504 | 106 / 504 | 6 / 504 |
| South Asian | 296 / 489 | 168 / 489 | 25 / 489 |
| American | 111 / 347 | 130 / 347 | 106 / 347 |
Counts of people, not modelled frequencies: every one of the 2,504 individuals sequenced by the 1000 Genomes Project phase 3, tallied by the genotype they carry. Deriving these from allele frequencies instead would assume random mating inside each group and undercount the homozygotes.
How to find out which you have
If you have taken a test with 23andMe, AncestryDNA, MyHeritage, Family Tree DNA, TellMeGen or Living DNA, this position is very likely already in the raw data file they gave you. You do not need another test.
One thing to watch if you look it up by hand: testing companies report some positions from one DNA strand and some from the other, and the file does not say which. Read the letters as they appear and you will get the opposite of the truth for some positions. Sequencings resolves that automatically.
Source
Coordinates and allele pair verified against Ensembl GRCh37. Direction of effect verified against VEP protein consequences or 1000 Genomes population frequency. Category: Trait.
Where this fits
Common questions
What is rs28777?
rs28777 is a position in the SLC45A2 gene on chromosome 5. 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.
What does it mean if I have AA at rs28777?
Lighter-skin version, two copies. Two copies of the lighter version, carried by the large majority of Europeans.
What does it mean if I have CC at rs28777?
Darker-skin version, two copies. Two copies of the higher-pigment version.
How do I find out my rs28777 genotype?
If you have taken a home DNA test, this position is very likely in the raw data file you were given. Sequencings reads that file in your browser without uploading it, and resolves which DNA strand each position was reported from, which is the step most manual lookups get wrong.
This is reference information, not medical advice, and not a diagnosis. See the medical disclaimer. Category: Trait.