" The unglamorous truth is that there are but a handful of uniquely human traits that we have clearly demonstrated are adaptations evolved to thrive in specific geographical regions. Skin color is one. The ability to digest milk is another, which fits perfectly with the emergence of dairy farming (again, discussed in Chapter 2). The best-understood example of regional adaptation concerns the single greatest cause of death in the human story. Genetic mutations emerged in populations in malaria regions that offer some protection against two versions of the disease, "

― Adam Rutherford , A Brief History of Everyone Who Ever Lived: The Stories in Our Genes