The natural selection that shapes our genomes

Most of the variation in the human genome (∼95%) is constrained, directly or indirectly, by purifying selection and GC-biased gene conversion, according to a recent article by Pouyet et al. (2018). The use of 'non-neutral' variation to infer human demographies can lead to undesirable biases; for example, in estimation of the time of the most recent common ancestor. Further examination of 'neutral' variation in entire human genomes from The 1000 Genomes Project reveals that ∼99% of this variation lacks exonic function, but ∼35% of it falls in introns. In addition, estimates of biogeographical ancestry using 'non-neutral' SNPs differ very marginally from inferences obtained from 'neutral' variation. Additional investigations should be carried out before establishing the roadmap for future human population and forensic genetic studies.