Genotyping for fun and profit.

The papers are reporting an announcement of cheap DNA sequencing (or, as they like to put it ‘decoding’).  The new machine claims to be able to produce a human whole-genome sequence for USD1000, or about $1250 at current exchange rates.  This is, allegedly, a “milestone in bringing nearer the possibility of routinely sequencing a person’s entire DNA in order to identify, and possibly correct, genetic defects that could lead to disease or death”.  It remains to be seen what the accuracy and cost of the machine will be in practical use.  The $1000 doesn’t include any of the cost of blood samples and DNA extraction. It also doesn’t include the high administrative costs of clinical-quality sample tracking: in large-scale research you might be able to accept a 1 in 1000 chance of two samples being accidentally switched, but not in clinical medicine

Medical uses of sequencing are certainly closer as the cost falls, but cost is far from the only barrier.  At the moment, we have very little clue as to what DNA sequence variants are even predictive of disease risk. Even if disease risk could be predicted usefully, which is far from obvious for most diseases, that isn’t worth much clinically unless you can do something about it.  We’ve had the ability to measure thousands of genetic variants at much lower prices than $1000 for years, and haven’t been able to think of much worth doing with it clinically.

The main current applications of DNA sequencing in New Zealand are in the dairy industry, precisely because tiny improvements in prediction are much more valuable in agriculture (where you can manipulate breeding) than in medicine. The Livestock Improvement Corporation has been a leader in using DNA information to select animals for breeding, and a lot more cows than humans have had their genomes sequenced.

In the short term, both agricultural research and medical research should benefit from more-affordable genotyping. It may become possible to do some larger-scale genetic epidemiology in New Zealand. But you shouldn’t hold your breath for the NHI system to start paying for genome sequencing.