Two Mysterious Ancestors Found in Our DNA

Topic: Genetics

Scientists at UC Berkeley have discovered two unknown human relatives whose DNA is present in people alive today. They found this by studying hundreds of modern human genomes and reconstructing ancient genealogical connections. The discovery adds to our understanding of human evolution as a history of encounters and interbreeding among many related hominin populations.

Scientists have discovered two previously unknown human relatives whose DNA is present in people alive today. This was found by studying hundreds of modern human genomes and reconstructing ancient genealogical connections. The discovery adds to our understanding of human evolution as a history of encounters and interbreeding among many related hominin populations.

One of the unknown groups, called a ghost ancestor, interbred with modern humans in Africa more than 50,000 years ago. This encounter took place before the most recent major movement of Homo sapiens out of Africa and into Europe and Asia. DNA inherited from this lineage makes up approximately 1% of the modern human genome.

The researchers also detected genetic material from an even more ancient population, which they call a super-archaic ancestor. This hominin descended from a lineage dating back about 1.8 million years and appears to have interbred with Denisovans in Eurasia, probably more than 200,000 years ago.

The findings suggest that early Homo sapiens lived alongside numerous related human groups in Africa and Eurasia during the past million years. These populations were genetically similar enough to have children together, leaving behind lasting biological traces.

Why It Matters

This discovery helps us understand how humans evolved over time and how different populations interbred. It also shows that our DNA is a mix of many different ancestors, not just Neanderthals and Denisovans as previously thought.

Key Facts

• Two unknown human relatives were discovered in modern human genomes.
• The ghost ancestor interbred with modern humans in Africa more than 50,000 years ago.
• DNA inherited from the ghost lineage makes up approximately 1% of the modern human genome.
• The super-archaic ancestor descended from a lineage dating back about 1.8 million years and interbred with Denisovans in Eurasia.
• Early Homo sapiens lived alongside numerous related human groups in Africa and Eurasia during the past million years.

Key Terms

Hominin

A member of the human-like species that includes modern humans, Neanderthals, and Denisovans.

Implications

This discovery helps us understand how humans evolved over time and how different populations interbred. It also shows that our DNA is a mix of many different ancestors, not just Neanderthals and Denisovans as previously thought.