Last year, at the American Society of Human Genetics meeting in Hawaii, Nick Eriksson gave a talk on 23andWe, the scientific arm of 23andMe. He reported a series of genetic association studies that used their customer base as a pool of active participants, by asking them to fill out questionnaires, and correlating their answers with their genotypes. They reported a few novel genes that were associated with semi-amusing/semi-serious traits, including a variant associated with curly hair, and the olfactory receptor variant that predicts whether or not you can smell asparagus in your own urine; these associations have since been published in PLoS Genetics.
This is all very interesting, but that’s not really what I want to talk about here. What I do want to talk about is the effect that knowledge of these results can have on the users of personal genomics, and how this could feed back into genetics research. Stay with me, I’m going somewhere with this.
In Hawaii, Nick Eriksson quoted an interesting result involving the gene ACTN3, and specifically the variant rs1815739, associated with endurance during exercise; they tested whether this variant correlated with whether customers considered themselves sprinters or endurance runners. Now, 23andMe also has a section on their customer website that talks about ACTN3, and informs individual customers of whether they have the endurance or the sprinter variant. Being relatively smart people, the researchers recorded which individuals in the study group had and had not viewed this page. While those that had not viewed the page showed no strong association between genotype and reported runner type, those that had viewed the page and knew they had the sprinter variant were significantly more likely to report that they were sprinters (and vice versa).
So, the self-reported runner type was influenced by what people believed their DNA told them about their runner type. Knowledge of your genotype can change your self-reported phenotype? Interesting, but perhaps not that surprising, and not really a problem for research, as we can just exclude these individuals, or, if they are too common, use objective measures that don’t rely on self reporting (heart rate, metabolite concentration, etc). But, I can’t help picturing a pair of customers completing the 23andWe survey, getting up and thinking “I’m an endurance runner… maybe I’ll run to Crystal Palace and back this afternoon!”, and “I’m a sprinter: I’m definitely trying out for Striker next season”. Think about how different these two people could be, physically, in 12 months? 23andMe may have created a genetic feedback loop.
Where could this lead to, especially when you take into account the influence of the pseudo-scientific reporting of genetics in parts of the media? Could the Daily Mail, by reporting a dodgy “Gene For” story, actually create a genotypic association between, say, OR51E2 and unemployment, by declaring those with a defective form of the olfactory receptor to be “more likely to be failures” or somesuch? What happens when it spreads out into families, creating strange genotype-phenotype associations by proxy? “We always went swimming as kids; Dad liked it, as he thought it would help prevent the muscle degeneration he thought he’d get because of his coding deletion in LMNA“.
We are talking here about creating an entirely new channel of genotype-phenotype causality, one that goes from Genotype, directly to Behavior, and then finally to Physical Traits; this will get even more complicated with psychiatric traits. Perhaps, ultimately, genetic researchers should be treasuring the current generation, who were born early enough to grow up while genetic testing is still rare enough to have no real influence on phenotypic development.