A study conducted by a genetic test manufacturer, 23andMe, Inc., based in Mountain View, Calif., confirmed nine known gene associations and found four new ones, Nicholas Eriksson, the principal investigator at 23andMe, and colleagues reported online in the journal PLoS Genetics.
"In this paper, we confirm that self-reported data from our customers has the potential to yield data of comparable quality as data gathered using traditional research methods," Anne Wojcicki, president and co-founder of 23andMe, said in a statement.
"We are excited about moving scientific research forward, faster," she added.
Ten years after the mapping of the entire human genome, there's been rapid growth in genome-wide data. Yet much of human genetic variation remains entirely unexplained, the researchers said. That's partially due to challenges with the efficient and coordinated collection of genotype and phenotype data.
The gene-test maker's customer database included about 10,000 participants who were given the option of contributing phenotype data via web-based surveys. So rather than having to recruit cases and controls, the researchers thought they could instead correlate physical characteristics or disease status with voluntarily-contributed genetic data to find single nucleotide polymorphisms (SNPs) linked to a trait or condition.
To test the feasibility of this idea, the 23andMe team decided to assess 22 traits.
In addition to confirming several of these gene associations, they also found four novel SNP associations in hair curl, the photic sneeze reflex, freckling and asparagus anosmia.
For asparagus anosmia -- the inability to detect the scent of certain asparagus metabolites in the urine -- the researchers found a region on chromosome 1 containing a cluster of olfactory receptor genes significantly associated with the ability to smell asparagus metabolites.
There's been debate over whether the trait is determined by the patient's ability to metabolize asparagus, or to detect the smell of the metabolite. The findings suggest "the genetic variation in this trait is in the ability to detect the odorant," they wrote.
"Our analysis not only identified new genetic associations, but also showed that our novel way of doing research -- collecting self-reported data over the web from involved participants who also receive interpretations of their genetic data -- is a viable alternative to traditional methods," they added.
Eriksson said another advantage of doing research this way is the ability to easily ask follow-up questions. Recruiting so many patients to a study at once also reduces the time and money needed to do research.
Finally, it assists in avoiding publication bias, because detecting negative results won't be so costly.
In an accompanying editorial, PLoS Genetics editors Greg Gibson of Georgia Institute of Technology in Atlanta, and Gregory P. Copenhaver of the University of North Carolina at Chapel Hill noted that informed consent could be an issue with such studies.
Still, they defended their decision to publish the present study without review of an institutional review board (IRB).