Monday, January 27, 2014
Human populations have undergone a recent rapid growth that is predicted to leave an excess of very rare variants (i.e. only a small number of individuals have them) in the population. Yet, purifying selection also leaves a similar signature when driving deleterious alleles to become rarer. Though recent studies have investigated the genetic impact of this rapid growth they have been confounded by selection since they focused on genes. To minimize the confounding effect of natural selection, Alon Keinan, Andy Clark and colleagues sequenced and analyzed genomic regions far from genes in ~500 individuals of European ancestry. The results point to a population growth of about 3.4% per generation over the last 3,000–4,000 years, resulting in a greater than 100-fold increase in population size over that epoch.
Article in Proceeding of the National Academy of Sciences USA: http://www.pnas.org/content/early/2013/12/26/1310398110.abstract