What SLC45A2 rs16891982 Means in Your 23andMe Raw Data

Your 23andMe raw data line for SLC45A2 rs16891982 tells you which copies of a pigmentation-related transporter you carry. A GG genotype has two copies of the G allele commonly associated with lighter skin pigmentation in European-ancestry studies; any hair or eye associations are secondary and population-dependent. CG is one copy. CC is neither copy. It is one of several variants associated with melanin baseline, not a single skin-color switch. This line is not a diagnosis, ancestry test, or skin-cancer risk assessment.

What does SLC45A2 rs16891982 mean in my 23andMe raw data? Open your 23andMe text file and search for rs16891982. You will see a line on chromosome 5 with two letters. rs16891982 is commonly seen as C/G in 23andMe exports, and G is the allele commonly associated with lighter pigmentation in European-ancestry studies. In European-based studies, C is associated with a higher melanin baseline. Read the letters exactly as 23andMe reports them. If the file has been converted or imported into another tool, confirm the allele labels still match the original export before interpreting.

The quick interpretation is:

The word baseline matters. This line cannot tell you your actual skin color. It says which version of one transporter you carry.

How the gene works: a transporter, not a pigment switch SLC45A2 makes MATP, the membrane-associated transporter protein. It sits in the melanosome, the cell compartment where melanin is made. MATP helps maintain the right environment for tyrosinase, the enzyme that actually produces melanin. rs16891982 is a missense variant in SLC45A2. The G allele is associated with a lighter pigmentation baseline in European-ancestry studies. This association does not mean the variant directly changes melanin production or deposition.

Here is the chain.

This is not a full loss. Full loss of SLC45A2 function causes oculocutaneous albinism type 4, a rare condition with very little pigment. The common rs16891982 variant is a mild dial, not an off switch.

Why one SNP does not decide your skin, eye or hair color People get this wrong. They see GG and assume blonde, blue-eyed and sunburned. That is not how it works. SLC45A2 is one input. HERC2/OCA2 is most strongly associated with eye color. MC1R is associated with red hair and freckling. SLC24A5, TYR, OCA2 and ASIP are also associated with pigmentation. A person with GG at rs16891982 can still have brown eyes and brown hair. The opposite also happens. The G allele is common in many European populations, so it does not separate blonde from dark-haired Europeans on its own. It is associated with a lighter baseline in much of Europe, then other variants layer on top. Outside Europe, allele frequencies and pigmentation architecture vary, so this SNP alone is less predictive.

SLC45A2 rs16891982 is associated with your baseline, not your final color. It acts with SLC24A5, OCA2, HERC2, MC1R and others, not instead of them.

Does GG change my skin cancer risk? rs16891982 alone is not a skin-cancer risk result. Pigmentation-related variants, including some in SLC45A2, are studied as part of broader risk patterns in some populations, but this single SNP cannot tell you your skin cancer risk. A dermatologist looking at sun damage, family history and the whole set of pigmentation markers will get more signal than this one line. It belongs in the pile of genetic hints, not a standalone warning.

What to check next in the same raw file Search these in your 23andMe file: - SLC24A5 rs1426654: another major light-skin allele, common in Europe and South Asia. - HERC2 rs12913832: the strongest common eye-color marker. - MC1R rs1805007 and related markers: red hair and freckling. - ASIP region variants: freckling and pigmentation-related melanoma risk. Together they give a better read than any single line.

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The download steps for 23andMe, on the page itself.

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The short version: what is worth acting on, first.

See it in your own numbers Upload your 23andMe file at HealthOS DNA. The file is parsed in your browser, and the immediate SLC24A5/SLC45A2 skin-sun trait story, HERC2/OCA2 eye-color prediction and MC1R hair-color result appear before any email is required. The full report opens after a free one-time email code.