Modern Humans Descended from Two Divergent Ancestral Populations

New research reveals a genetic mixing event 300,000 years ago between populations that split 1.5 million years ago, reshaping our understanding of human evolution.

The study identifies two ancestral populations, one contributing 80% and the other 20% of modern human DNA, with the latter influencing brain function and neural processing.
Researchers used the cobraa algorithm and modern human DNA from the 1000 Genomes Project to model ancient population splits and reunions.
The genetic mixing event 300,000 years ago was significantly larger than later interbreeding with Neanderthals and Denisovans, affecting all modern humans.
One ancestral population experienced a severe bottleneck after diverging, shrinking to a small size before recovering over a million years.
The findings challenge the single-lineage model of human evolution, highlighting interbreeding and genetic exchange as recurring patterns across species.