Extended Data Figure 5: Fewer accumulated mutations in Africans than in non-Africans confirmed by mapping to chimpanzee.
From: The Simons Genome Diversity Project: 300 genomes from 142 diverse populations
We compute a statistic D (Population A, Population B, Chimp), measuring the difference in the rate of matching to chimpanzee in Population A compared to Population B. The evidence of mismatching to chimpanzee is seen when we restrict to the male X chromosome to eliminate possible effects due to differences in heterozygosity across populations, and map to the chimpanzee genome which is phylogenetically symmetrically related to all present-day humans. We find that in 78 randomly chosen Population A = African and Population B = non-African pairs of males, transversion substitutions show no consistent skew from zero, but transition substitutions do.
