Study looks at 'out of Africa' migration

Canadian researchers say new discoveries in Africa may lead to changes in assumptions of how, when and from where our ancestors left the continent. Explorations in southern Tanzania yielding fossils and other evidence of the beginnings of our own species, Homo sapiens, may be key to answering questions about early human occupation and the migration out of Africa about 60,000 to 50,000 years ago, the University of Alberta reported Thursday. Anthropologist Pamela Willoughby and her team of researchers uncovered artifacts suggesting continuous human occupation between modern times and at least 200,000 years ago, including a late Ice Age period when a near extinction-level event, or "genetic bottleneck," probably occurred. The bottleneck theory explains why the mitochondrial DNA of living people shows that all non-Africans are descended from one lineage of people who left Africa about 50,000 years ago. "It was only about 20 years ago that people recognized that modern Homo sapiens actually had an African ancestry, and everyone was focused on looking at early Homo sapiens in Europe who appeared around 40,000 years ago," she said. "But we now know that as far as back as around 200,000 years ago, Africa was inhabited by people who were already physically exactly like us today or really close to being the same as us. All of a sudden, it's not Europe in this time period that's really important. It's Africa."