References form the basis of our comprehension of the world: they enable us to measure the height of our children or the efficiency of a drug. But when such yardsticks are faulty, doubts are cast on all the measurements that derive from them. Geneticists too use standards to reconstruct the history of a species or to evaluate the impact of mutations, in the form of genetic markers scattered throughout the genome. Provided these markers are neutral, i.e. that they have evolved randomly rather than through a selective process, they can be reliably used as ‘standards’ to compare various parameters across populations. However, what scientist Fanny Pouyet and colleagues from the Group of Laurent Excoffier at SIB and University of Bern recently discovered, is that 95% of our genome actually seems to be affected by selection and other genetic biases and that markers previously thought to be neutral appear to provide skewed estimates. Their study, published in eLife, calls for the re-examination of a plethora of results and provides the tools and recommendations to correct such issues in the future.

genome under influenceSetting a standard of reference: creation of the metre-alloy in 1874 at the Conservatoire des Arts et Métiers

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Reference
Pouyet F et al. Background selection and biased gene conversion affect more than 95% of the human genome and bias demographic inferences. eLife 2018;7:e36317 doi: 10.7554/eLife.36317