Bad Science: Genetic Signatures of Centenarians


A newsworthy study about a genetic signature of centenarians published in Science has not stood up to scrutiny by the blogosphere and peer scientists and has now been formally retracted by the authors.

Until recently, such retractions - whether by Editors or by the authors themselves - have been quite rare. With the blogosphere and 24/7 news media becoming more and more prominent, I suspect that we may begin to see more examples. Ultimately, it is a healthy process and good for science.

Below is an excerpt, with my emphasis, from their Letter to Editor in Science:

...we discovered that technical errors in the Illumina 610 array and an inadequate quality control protocol introduced false-positive single-nucleotide polymorphisms (SNPs) in our findings. An independent laboratory subsequently performed stringent quality control measures, ambiguous SNPs were then removed, and resultant genotype data were validated using an independent platform. We then reanalyzed the reduced data set using the same methodology as in the published paper. We feel the main scientific findings remain supported by the available data: (i) A model consisting of multiple specific SNPs accurately differentiates between centenarians and controls; (ii) genetic profiles cluster into specific signatures; and (iii) signatures are associated with ages of onset of specific age-related diseases and subjects with the oldest ages. However, the specific details of the new analysis change substantially from those originally published online to the point of becoming a new report. Therefore, we retract the original manuscript and will pursue alternative publication of the new findings.

Their retraction emphasizes the importance of good controls in any experiment as well as reliable statistics. Interestingly, scientists at 23andme reported problems with this study in a blog post only six days after the original publication of the study in question.

Here's an excerpt, with my emphasis:

There are several reasons for skepticism about these new results. Another recent genome-wide study has reported no significant associations with longevity. There is suggestive evidence of genotyping quality control problems in the new results, and some routine quality control checks do not appear to have been done. The design of the study is particularly susceptible to introducing biases into the results. And a preliminary analysis of the proposed 150-SNP model for predicting longevity indicates that it is not predictive in the 23andMe community.

We repeated our analysis restricted to individuals with European ancestry. The results were similar: for 129 customers with age ⥠95 and more than 43,000 controls, we got a test statistic of 0.534, and for 26 customers with age ⥠100, we got a value of 0.558. In both cases, the 95% confidence interval includes 0.5.

This retraction does not prove that there is no genetic component to living a long, healthy life. It is, however, an important example of how the blogosphere and fellow scientists are a key element in peer review and that science is always self correcting.

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