23andme measures presence / absence of ~1M specific single-nucleotide polymorphism mutations (a SNP is a change in one "letter" of DNA), out of 10M+ total mutat

23andme measures presence / absence of ~1M specific single-nucleotide polymorphism mutations (a SNP is a change in one "letter" of DNA), out of 10M+ total mutations known SNP mutations. Whole genome sequencing reads basically your entire genome, which consists of approximately 3 billion base pairs so 23andme is like a unit test, and WGS is like the source code for the whole system that said, we don't really know how to interpret most of the source code, so for a lot of cases (esp those that don't relate to medical treatment or research), 23andme is probably fine