Ancient Proteins Reveal Homo erectus as Possible Denisovan Ancestor, Suggesting Early Human Interbreeding

Ancient Proteins Shed Light on Early Human Interbreeding

Advances in ancient DNA analysis have clarified key aspects of human ancestry, revealing that early humans interbred with Neanderthals and Denisovans as they migrated out of Africa. Evidence from the Denisovan genome further indicates that such interbreeding was not unprecedented—Denisovans themselves had likely interbred with an even earlier hominin group. However, the identity of this mystery group remained unclear.

Homo erectus Identified as Possible Ancestor of Denisovans

New research based on ancient proteins extracted from Homo erectus teeth suggests that this early human species may have been the mystery group. Homo erectus left Africa over a million years ago and spread across Eurasia, but their DNA has been difficult to recover due to degradation over time. Proteins, however, degrade more slowly than DNA, providing a new window into the past.

How Ancient Proteins Provide Clues

Unlike DNA, proteins in ancient remains can persist long after genetic material has broken down. While DNA degrades rapidly without cellular repair enzymes—fragmenting and losing bases—proteins offer a more durable alternative. Cooler, drier environments slow this process, but even then, DNA recovery becomes nearly impossible beyond a certain point. Proteins, however, can survive in a recognizable form for far longer, allowing scientists to extract meaningful biological information from much older specimens.

Denisovans May Have Passed Homo erectus DNA to Modern Humans

The study suggests that Denisovans interbred with Homo erectus, and some of this ancient DNA may have been passed down to modern humans. This finding adds a new layer to our understanding of human evolution, indicating that genetic mixing between early human species occurred far earlier than previously thought. The research underscores the complexity of our ancestry and the interconnected history of human populations.

Implications for Human Evolution

The discovery highlights the importance of non-DNA methods, such as protein analysis, in uncovering the secrets of ancient hominins. As technology advances, scientists may continue to uncover new details about the interactions between early human species, reshaping our understanding of how modern humans came to be.