The genetics of human migrations

Abstract

When our human ancestors began to migrate from the African savannahs across the Alps into Northern Europe and Asia between 200,000 and 60,000 years ago, they encountered a colder climate, different food sources and new predators. Inevitably, evolution began to work on those wandering tribes: their skin became lighter, their metabolism adapted to new food sources, and their immune system had to handle different pathogens. Modern Homo sapiens began to evolve into slightly different subspecies or, as they are referred to in the common vernacular, different races. This shallow notion of race—that differences in our appearance have deep‐seated consequences for who and what we are as human beings—is the root of racism, which has led to slavery, discrimination, murder and genocide throughout the millennia. With the emergence of modern genetics and genomics, scientists had hoped that a better understanding of genetic differences and similarities among humans would eventually help to overcome the controversial and toxic notion of race as having anything to do with a person's ability, intelligence or humanity. As J. Craig Venter, then head of the Celera Genomics Corporation in Rockville, MD, USA, put it in 2000, when the first draft of the human genome was published: “Race is a social concept, not a scientific one”. Since the publication of the human genome, further advances in genomic sequencing and statistical analysis are now yielding new insights into the link between past human migrations and today's variety of genetic differences that govern disease resistance, skin pigmentation, tolerance to cold, and ability to digest or metabolize various nutrients. Such findings are contributing to discussions around the delicate issues of race, ethnicity and identity, but they are also having a significant impact on biomedical research and personalized health care. Furthermore, genetic analysis is shedding light on the migrations themselves, along with …