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Graphs Show Costs of DNA Sequencing Falling Fast
kkleiner writes "You may know that the cost to sequence a human genome is dropping, but you probably have no idea how fast that price is coming down. The National Human Genome Research Institute, part of the US National Institute of Health, has compiled extensive data on the costs of sequencing DNA over the past decade and used that information to create two truly jaw-dropping graphs. NHGRI's research shows that not only are sequencing costs plummeting, they are outstripping the exponential curves of Moore's Law. By a big margin."
Actually, they're not sequencing.
They're checking.
The way 23andme and most personal genome companies work is that they have those genochips (Illumina) with one million DNA sequences on them, and they check whether or not your DN has one of those sequences.
If you have a SNP not on the chip (well, you have lots of SNP not on the chip), it won't list anything. If, at a given chromosome locale, they have "all" of the "known" SNP, but you happen to have a mutant variant not on their lib, then you're not detected.
"Sequencing" involves taking your DNA, and getting every sequence, no matter what. And that's still long and very expensive. We're in the era of the "thousand genomes", meaning we expect in a couple year to complete a thousand full sequences. Of course, 10 years later, we'll sequence everyone, but, so far, it's still a way out.
'Also, my understanding is that most uses don't require sequencing the entire genome, but rather just a small subset of it.'
Very small subsets (e.g. individual genes) are still done the 'traditional' way (1990s technology!). Intermediate subsets (like the 'exome') are now done using a pre-selection 'capture' process ('target enrichment') followed by analysis on the same 'next generation' instruments that are used for whole genomes. Right now, this makes sense economically, since it requires less capacity (fewer consumables and less run time) on the expensive sequencers. But as sequencing prices continue to drop, we'll probably reach a point where it's cheaper to do the whole genome than any significant subset (since the 'capture' process is also fairly expensive). Cheaper to do the wet lab stuff, anyway - whole genomes also require much more processing power than useful subsets like exomes.