unz | Middle Eastern, North African, and Pakistani populations are even more extreme. You can see it in the figure above. Across short runs of homozogosity the results converge onto what you’d expect, roughly. But Middle Eastern populations are a huge anomaly at long runs. That’s because of this:
From 20–50% of all marriages in the GME are consanguineous (as compared with 0.2% in the Americas and Western Europe)1, 2, 3, with the majority between first cousins. This roughly 100-fold higher rate of consanguinity has correlated with roughly a doubling of the rate of recessive Mendelian disease19, 20. European, African, and East Asian 1000 Genomes Project populations all had medians for the estimated inbreeding coefficient (F) of ~0.005, whereas GME F values ranged from 0.059 to 0.098, with high variance within each population (Fig. 2c). Thus, measured F values were approximately 10- to 20-fold higher in GME populations, reflecting the shared genomic blocks common to all human populations. F values were dominated by structure from the immediate family rather than historical or population-wide data trends (Supplementary Fig. 8). Examination of the larger set of 1,794 exomes that included many parent–child trios also showed an overwhelming influence of structure from the immediate family, with offspring from first-cousin marriages displaying higher F values than those from non-consanguineous marriages (Fig. 2d).