Why Are Alleles for This SNP Different Elsewhere?

DNA has two strands, often labeled as “positive (+)” and “negative (-)”. The same SNP has different (complementary) alleles on each of these strands.

Some studies and resources report SNPs as they appear on the negative (-) DNA strand, while every SNP in the SelfDecode database is reported on the positive (+) DNA strand.

“A” on the positive strand corresponds to “T” on the negative, and vice-versa. 

“C” on the positive strand corresponds to “G” on the negative, and vice-versa. 

For example, if your genotype for a particular SNP is “AG” at SelfDecode, don’t be surprised to see “TC” elsewhere.

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