[crispyambulance]

23andMe uses genotyping. IANAMB, but I think that means they run a series of assays each of which "examines" a small PART of the genome to look for something very specific.

As part of their process, however, they could extract the DNA and keep a sample frozen for later assays or even full genome sequencing but I don't know if they do that.

https://customercare.23andme.com/hc/en-us/articles/202904600...

[cjbprime]

They give you the option when you sign up, of retaining your sample for later sequencing runs on newer/more comprehensive hardware, or discarding it.