English: Inferred history of chromosomes for individual populations. Each frame shows the path that chromosomes took from their origin in Southern Africa in reaching the population labelled in each frame. The width of each line indicates the proportion of the chromosomes that travelled by that route, with the diameter of the circle indicating the total proportion of chromosomes that went via that location (diameter of San  =  1.0). Values were estimated recursively, working backwards from the labelled population to the first by assuming that the amount of genetic material passed on by each population was proportional to the number of donor individuals it contributed. Numerical values are given in Table S3 and Table S4 .