[ymc]

I don't see a reason for 23andme to store all the read data for a genome sequence. It isn't like their typical user will fire up IGV and peruse the BAM file. [Note: I just noticed that their new "Golden Helix" browser is for that purpose. Pretty crazy...] Storing the data as a diff against some reference sequence would be plenty.

Anyway, the core of my argument is that storage costs are not likely to be what drove 23andme to do exon sequences, instead of full genomes. Sequence still costs orders of magnitudes more to obtain than to store. Even when total cost to obtain a human genome sequence drops to $1000, storage will still be a minor component of its total cost.

However, rather than churn through a few more cycles of this dispute, maybe we could look for the price at which we would both agree that storage becomes a substantial part of the cost of obtaining a genome sequence.

Around $100/genome, the cost of transiently storing the read data will begin to consume enough of a budget that it will be considered a major factor, I think. Of course other computation aspects will also be felt -- CPU time, band width, etc.

The thing is, below a certain cost per genome, it may no longer make sense to store anything other than the processed data. That is, DNA itself serves as the storage medium if additional information needs to be gleaned. Or, in other words, the information is already stored in the primary structure of the DNA. We are really just paying to "down convert" it from molecular to digital storage.

Note that as long as the price of obtaining sequence continues to fall at a rate below the rate at which cost to store sequence decreases, the problem of storing the digital form only gets harder. So that is why that even if I disagree about storage being a major factor in the cost of a $1000 genome, I agree that it does become a major factor at $100/genome.

Of course that leaves us 10-fold from agreeing with one another. But that is, nevertheless, a quantitative disagreement, not a qualitative one.

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Phillip

Thanks for your thoughtful reply. I am just a home-bound NGS hobbyist. Here is another food for thought from someone who works for a big genome center:

http://nextgenseq.blogspot.hk/2011/10/sequence-squeeze.html