Evidence for Hitchhiking of Deleterious Mutations within the Human Genome
The rate of low, intermediate and high frequency deleterious polymorphism measured by θW (black), θπ (red) and θH (blue), respectively, before (crosses) and after (squares) a single hitchhiking event (A) and in the presence (crosses) and absence (squares) of multiple hitchhiking events (C). Average heterozygosity (θπ) of neutral polymorphism is shown in gray. The ratio of deleterious to neutral polymorphism is shown before (crosses) and after (squares) a single hitchhiking event (B) and in the absence (crosses) and presence (squares) of multiple hitchhiking events (D). All panels show the mean of 500 simulations for which 4Nun = 70, 4Nud = 70, 4Nsd = −10 and 4Nsa = 100, where N is the population size, u is the mutation rate, s is the selection coefficient, and subscripts n, a and d refer to neutral, advantageous and deleterious mutations. In panel A and B, a single hitchhiking event occurs at the center of the chromosome. In panel C and D, 4Nua = 0.5 and multiple hitchhiking events occur across the entire chromosome.