A novel genetic model suggests that the ancestors of modern humans came from two distinct populations that split and reconnected during our evolutionary history.

© new-science.ruA new study details how human ancestors mixed with a mystery population 300,000 years ago.
The ancestors of all modern humans split off from a mystery population 1.5 million years ago and then
reconnected with them 300,000 years ago, a new genetic model suggests. The unknown population contributed 20% of our DNA and may have boosted humans' brain function.
"The fact that we can reconstruct events from hundreds of thousands or millions of years ago just by looking at DNA today is astonishing, and it tells us that our history is far richer and more complex than we imagined," study co-author
Aylwyn Scally, a geneticist at the University of Cambridge, said in a
statement.
In a study published Tuesday (March 18) in the journal
Nature Genetics, researchers presented a new method of modeling genomic data, called "cobraa," that has allowed them to trace the
evolution of modern humans (
Homo sapiens).
By applying their new method to modern human DNA data published in the 1000 Genomes Project and the Human Genome Diversity Project, the researchers discovered that there were two main ancestral groups that split around 1.5 million years ago, which they called Population A and Population B.
Just after that split, Population A experienced a bottleneck when the population plummeted and likely lost a significant amount of genetic diversity. But Population A grew over time, and
Neanderthals and
Denisovans branched off from it.
Then, around 300,000 years ago, Population A mixed with Population B, the researchers found. Their genetic analysis suggests that 80% of the genome of all present-day humans comes from Population A, while 20% of our genome comes from Population B.
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