In the last two decades, genetic research has gone through a technological revolution and is now producing unprecedented amounts of data on individuals and human groups. The interpretation of data from human evolutionary genetics—along with sources from history, archaeology, linguistics, anthropology, and paleontology—is changing our understanding of human history.

We all come from Africa, where our ancestors lived over a hundred thousand years ago. We all belong to the same species, Homo sapiens, and our DNA is more than ninety-nine percent identical. The amazing diversity we see when we look at one another cannot be analyzed according to human “races.” Our genetic diversity primarily exists between individuals, not between groups. Some of the genetic differences in our species, however, follow geographic patterns, which reflect previous environmental challenges, cultural encounters, and population movements. They are a product of constant interaction between genes, environments, and social conditions.

Research on human biological variation still raises difficult scientific, political, social, and ethical questions. These are related to the language, methods, and theories used in research, interpretation and communication of results, as well as to access to human biological material.