[jacquesm]

Yes, you're right, sorry about the confusion. The point I was trying to make was they give you the 'limited' version, but you give them everything. They may not sequence it all today but they could do so in the future (I'm assuming they keep copies), and they could sell your samples to parties that can sequence it all (today or in the future).

[infinite8s]

From their privacy policy (https://www.23andme.com/legal/privacy/) it seems they destroy the sample after generating the SNP map (Personal Info section, Genetic Info subsection paragraph 1).

[jacquesm]

You're right. I missed that, they contract out the sequencing though.

You seem to be pretty knowledgeable here, how much information is still present in those SNP maps (in terms of bits per person)? Would an SNP map still uniquely identify an individual ?

[infinite8s]

It depends on how many SNPs (read as 'snip') they map and how much variation is at each site. It basically boils down to a combinatorial counting problem, although there is the complication that variation across close SNPs might not be independent (especially if they are on the same gene, or are related in some phenotypic way).

This is also the basis for DNA forensics/paternity tests. If you sample enough SNP locations you should theoretically have a unique signature (this is where you get the courtroom statistic of 1 in 3 million)

[jacquesm]

A bit after the fact, but apparently they have the option to 'biobank' your saliva, which means they store it for the longer term. It would be interesting to know how many people use that option.