Recent Single Origin Hypothesis

Recent Single Origin Hypothesis

In paleoanthropology, the recent African origin of modern humans, frequently dubbed the "Out of Africa" theory, is the most widely accepted model describing the geographic origin and early migration of anatomically modern humans. The theory is called the (Recent) Out-of-Africa model in the popular press, and academically the recent single-origin hypothesis (RSOH), Replacement Hypothesis, and Recent African Origin (RAO) model. The hypothesis that humans have a single origin (monogenesis) was published in Charles Darwin's Descent of Man (1871). The concept was speculative until the 1980s, when it was corroborated by a study of present-day mitochondrial DNA, combined with evidence based on physical anthropology of archaic specimens.

Genetic studies and fossil evidence show that archaic Homo sapiens evolved to anatomically modern humans solely in Africa, between 200,000 and 150,000 years ago, that members of one branch of Homo sapiens left Africa by between 125,000 and 60,000 years ago, and that over time these humans replaced earlier human populations such as Neanderthals and Homo erectus. The date of the earliest successful "out of Africa" migration (earliest migrants with living descendants) has generally been placed at 60,000 years ago as suggested by genetics, although migration out of the continent may have taken place as early as 125,000 years ago according to Arabian archaeology finds of tools in the region. A 2013 paper reported that a previously unknown lineage had been found, which pushed the estimated date for the most recent common ancestor (Y-MRCA) back to 338,000 years ago.

The recent single origin of modern humans in East Africa is the predominant position held within the scientific community. There are differing theories on whether there was a single exodus or several. A multiple dispersal model involves the Southern Dispersal theory, which has gained support in recent years from genetic, linguistic and archaeological evidence. A growing number of researchers also suspect that "long-neglected North Africa" was the original home of the modern humans who first trekked out of the continent.

The major competing hypothesis is the multiregional origin of modern humans, which envisions a wave of Homo sapiens migrating from Africa and interbreeding with local Homo erectus populations in multiple regions of the globe. Most multiregionalists still view Africa as a major wellspring of human genetic diversity, but allow a much greater role for hybridization.