Scientists have discovered over 100 million SNPs that occur across the world's population. There is no genetic testing technology that can detect that many potential variants in a single test array. Therefore the genome is sampled initially by genetic wide association studies (GWAS) to find likely hotspots where a more focused search can then be performed. Even then, scientists do not know exactly where to look for the actual functional mutation(s) that may be causing a change in enzyme activity as most SNPs are innocent and do not cause any change to the enzyme. Tag SNPs evolved as a convenient and economical way to bookmark or tag a SNP that gets inherited together with the (yet undiscovered) functional mutation or group of mutations. A tag SNP is similar to an innocent bystander. They are not the guilty party, but almost always are found nearby.
Articles in this section
- Why Doesn’t StrateGene Report on APOE SNPs?
- My notable variation for a haplotype says "indeterminate" - what does this mean?
- How come the StrateGene SNP list is so different from what I am reading elsewhere online?
- How accurate are the COMT Haplotype speeds?
- How important is MAT1A in the SAM/methionine story?
- My COMT speed (specifically V158M/RS4680) was different in a previous StrateGene report than what is being reported here in my new StrateGene. Why is this?
- What does “increased risk” mean?
- How can I find more information about a particular SNP?
- I see results reported as NA, NC, or "indeterminate". What does this mean?
- What is meant by "tag SNP"?