We Are All Africans
For decades, paleoanthropologists have argued over two competing theories about the origin of our kind. The older notion, which owes its crude beginnings to Charles Darwin, is the Out of Africa hypothesis. This theory maintains that modern humans evolved in Africa and then spread around the world. Boiled down to its essence, the hypothesis states that modern humans are both relatively recent (100,000 to 200,000 years old) and African in origin. A major prediction of this hypothesis is that the earliest remains of modern humans will be found in Africa, dated to an appropriate time period.
The rival Multiregional hypothesis argues that modern humans evolved in many locations around the world from a precursor species, Homo erectus, approximately one to two million years ago. According to this school of thought, these regional populations evolved along parallel paths and reached modernity at roughly the same time. Because the populations were largely isolated from one another, they developed distinctive regional features, which people recognize today as "racial" differences. The Multiregional hypothesis predicts that the fossilized remains of the earliest modern humans will be found all over the Old World and that these scattered fossils will all date from about the same time. Furthermore, the theory requires these early populations to show anatomical and genetic continuity with the current inhabitants of the same region. For example, Multiregionalists believe that Neandertals, an archaic human form, are most closely related to modern indigenous Europeans.
Unfortunately for adherents of the Multiregional hypothesis, recent results are weighing heavily against them. Three very different strains of evidence have converged to offer convincing support for the rival theory.