Genetic bases of human biodiversity: an update.

The massive efforts to study in detail the human genome have produced extraordinary amounts of genetic data. Although we still fail to understand the molecular bases of most complex traits, including many common diseases, we now have a clearer idea of the degree of genetic resemblance between humans and other primate species. We also know that humans are genetically very close to each other, indeed more than any other primates, that most of our genetic diversity is accounted for by individual differences within populations, and that only a small fraction of the species’ genetic variance falls between populations and geographic groups thereof. However, population differences are large enough for patterns to emerge, and these patterns have been extremely useful to reconstruct the history of human migration and to recognise the effects of reproductive isolation. In many cases, crucial information about human demographic history has emerged from multidisciplinary analyses, which have stressed the importance of cultural, as well as geographical, barriers in causing local divergence of populations.