Researchers have used distinct markers from human subpopulations to trace back to our common African root in a giant human "tree ... the ancestress of all of modern humanity lived only 200,000 ...

Modern humans descended from not one, but at least two ancestral populations that drifted apart and later reconnected, long before modern humans spread across the globe.

For a long time, scientists believed the first humans to arrive in the Americas soon killed off these giant ground sloths ...