How do companies like 23andMe figure so much stuff out just by a using a saliva sample?

Question

How do companies like 23andMe figure so much stuff out just by a using a saliva sample?

In: Biology

Answer 1

They take DNA samples from your saliva and then use that as a template for the DNA tests they do in their labs. DNA is very small and there is a ton of it in every cell, let alone the tons of cells they would get from a saliva sample (usually check or tongue cells that have been scraped off).