What SLC24A5 rs1426654 Means in Your 23andMe Raw Data
What SLC24A5 rs1426654 means in 23andMe raw data: how to read A/A, A/G and G/G and what it does not say about skin color.
In a 23andMe raw data file, rs1426654 is a single nucleotide polymorphism in the SLC24A5 gene. Your result will be A/A, A/G, or G/G. The A allele at rs1426654 is associated with lighter skin pigmentation because it reduces the amount of dark eumelanin pigment produced, so A/A tends to mean less UV buffering, more sunburn tendency and less tanning. G/G tends to mean more eumelanin and more natural UV protection. This one marker does not give your exact skin tone or assign a race.
What does SLC24A5 rs1426654 mean in my 23andMe raw data?
SLC24A5 codes for a protein called NCKX5, a potassium-dependent sodium/calcium exchanger that works inside melanosomes, the small pigment factories inside melanocytes. The rs1426654 variant changes amino acid 111 of the protein from alanine to threonine. That single change disturbs the ion exchange enough to reduce the amount of eumelanin the melanosome produces. Eumelanin is the dark brown or black pigment that absorbs ultraviolet light, so less of it means lighter skin and a thinner built-in UV shield.
rs1426654 tells you which variant you carry at one strong pigmentation gene. It does not tell you your race, your exact skin color, or exactly how your skin will respond to sun.
The effect is not a one-to-one map. Skin color is polygenic. SLC24A5 is one strong contributor, but SLC45A2, OCA2, HERC2, ASIP, MC1R and many other genes push melanin production up or down. Sun exposure and age change the visible result too. The original human genetics work estimated that this one missense change accounted for about 25-38% of the pigmentation difference between African and European samples.
What A/A, A/G and G/G look like in your raw file
The genotype line in a 23andMe file usually shows rs1426654 with a chromosome position and two alleles. The table shows the direction, not a clinical label.
| Genotype | Pigmentation tendency | Sun response |
|---|---|---|
| A/A | Less eumelanin, lighter baseline | More sunburn tendency |
| A/G | Intermediate, other genes matter | Intermediate |
| G/G | More eumelanin, darker baseline | More UV buffering |
Scroll the table sideways for the rest →
Expected direction in 23andMe orientation. This is a single-gene tendency, not a clinical prediction.
What people get wrong about this SNP
The common mistake is to read A/A as "European" and G/G as "African". That is wrong. East Asian reference panels show the A allele near fixation, so many East Asian people carry A/A or A/G, not G/G, and East Asian light skin involves multiple light-skin alleles. Many South Asian, Middle Eastern and North African people carry A/A or A/G and have a wide range of skin tones. rs1426654 is an ancestry-informative marker because its allele frequency differs sharply between some regions, but one SNP cannot classify ancestry. It is used alongside thousands of other markers in ancestry models.
Reference data show the A allele near 100% in many European groups, below 2% in many West African groups, and near fixation in many East Asian groups. South Asian, Middle Eastern and North African groups fall across a wide range. That frequency split is why raw DNA tools surface this marker, but it works as one small piece, not as a single-locus verdict.
Can I have A/A and still have darker skin?
Yes. A/A shifts the baseline toward less eumelanin, but it does not wipe out the other pathways that make pigment. Some people with A/A still tan well because other pigmentation genes and repeated sun exposure increase their melanin production. Some G/G carriers have lighter skin for the opposite reason. If your skin tone does not match the expected rs1426654 result, the other genes are likely doing more work, or your ancestry background includes combinations where this marker is not the main determinant.
What it means for sun response
The practical read is simple. A/A is more likely to mean less natural UV buffering, so baseline sunburn risk goes up and tanning response may be weaker. G/G is more likely to mean more eumelanin, so baseline UV buffering is higher. A/G sits in between but not always neatly. Personal burn time also depends on UV index, time of day, altitude, prior exposure, age and individual skin barrier.
- A/A: less eumelanin, so baseline sunburn risk tends to be higher.
- A/G: the genetic input is intermediate, but other genes decide the visible result.
- G/G: more eumelanin and a stronger baseline UV buffer.
The download steps for 23andMe, on the page itself.
The short version: what is worth acting on, first.
If you want the same view for your own file, the free DNA tool at HealthOS /dna reads 23andMe raw data in the browser and reports this marker alongside other traits, medication response, carrier-relevant findings and an optional ancestry breakdown. No account is needed for the first trait story.
New to raw DNA files? Start with the full guide: How to Download & Analyze Your 23andMe Raw Data Free
Written by
HealthOS Research