Comparative analyses of human genomes show a decrease in genetic diversity as distance from Addis Ababa, Ethiopia increases. Ashraf and Galor have a paper that looks at the effect of genetic diversity on economic development (per capita income). Their idea is that middle levels of genetic diversity balances the social costs of high diversity and the creative benefits of variability in cognitive skills.
They find the optimal level of diversity currently is 0.72 which is an increase from 0.68 around 1500. The country with the highest diversity is Ethiopia (0.77) with Bolivia at the low end (0.63). The United States is at 0.72.
The authors estimate that genetic diversity accounts for 16% of the variation in per capita income. They project that if the US diversity were to change to either 0.71 or 0.73 then per capita income would decrease by 1.9%.
The “Out of Africa” Hypothesis, Human Genetic Diversity, and Comparative Economic Development