Change in haplotype heterozygosity between African agriculturists and East Asians. All sets of five consecutive X-linked SNPs were assembled into haplotypes. Haplotype heterozygosity was then calculated for all haplotypes in the Yoruba and the Han. The abscissa represents the chromosomal position of the center SNP while the ordinate gives the value of the Han heterozygosity as a proportion of the Yoruba heterozygosity (Han heterozygosity/Yoruba heterozygosity). The green data points represent haplotypes centered between 65 and 67 Mb and the blue data points represent haplotypes centered between 108.6 and 112.2 Mb.