Genetic Diversity, Population Density, and Per Capita Income

In an article published in 2013, Ashrof and Gaylor claim to have empirically established the hypothesis that degree of genetic heterozygosity within a population, as a function of migratory distance from East Africa, has a significant effect upon comparative economic development and that there is an optimal level of heterozygosity. Key to their analysis are two assumptions: First, that heterozygosity of neutral microsatellite markers is a valid proxy for functional genetic heterozygosity; and second, that there exist relatively accurate estimates of global population densities circa 1500 CE, and in particular for Africa, the Americas, and Oceana. We demonstrate that both of these assumptions are false and that consequently, Ashraf and Gaylor have not established their hypothesis.