for National Geographic News
We are solely children of Africa—with no Neandertals or island-dwelling "hobbits" in our family tree, according to a new study.
Scientists who compared the skulls and DNA of human remains from around the world say their results point to modern humans (Homo sapiens) having a single origin in Africa.
The study didn't find any evidence to suggest that human species living elsewhere in the world contributed to our direct ancestors' make-up.
A team led by Andrea Manica at the University of Cambridge, England, combined analysis of global genetic variations with comparisons of more than 6,000 skulls from more than a hundred ancient human populations.
The team found that loss of genetic diversity was very closely mirrored by reduced physical variation the farther away people lived from Africa. (Explore our human roots.)
Only Out of Africa
The new data support the single origin, or "out of Africa" theory for anatomically modern humans, which says that these early humans colonized the planet after spreading out of the continent some 50,000 years ago.
In the past, experts have also argued a "multiregional" theory, which held that Homo sapiens arose from different human populations in different areas of the world.
"The origin of anatomically modern humans has been the focus of much-heated debate," lead author Manica said.
"We have combined our genetic data with new measurements of a large sample of skulls to show definitively that modern humans originated from a single area."
Previous studies have found that genetic differences in human populations can be explained by distance from Africa.
The new study also looked at 37 measurements from male and female skulls from around the world. The chosen skulls were all less than 2,000 years old, making them better preserved and more likely to give accurate measurements than older skulls.
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