Our Ancestors' Chipped Teeth Are Taking Scientists Further Back in Time Than Ever Before

[Judi Lynn]

Researchers salvage ancient proteins to learn more about human ancestors.
By Bridget Alex December 4, 2020 8:00 AM

The individuals never mingled because they lived nearly 3,000 miles and 1 million years apart. But a chipped tooth from each met the same end — dissolved in acid at the University of Copenhagen.

These human ancestors, who roamed different patches of Eurasia roughly 1.77 million and 800,000 years ago, respectively, share a claim to fame: Their fossilized teeth harbored the oldest surviving proteins from extinct human species — molecules more than twice as old as human DNA. The strings of protein code, reported last April in Nature, provide long-sought details about a patchy chapter of our evolution.

Anthropologists know a good deal about hominins — humans and our fossil relatives — who evolved in Africa before 2 million years ago. Then hominin groups began spreading to Eurasia. Some of these early pioneers went extinct, while others led to later species like Neanderthals.

Researchers have struggled to fit these ancient Eurasians into our evolutionary tree based on the look of their bones. DNA could settle the matter, but the molecules usually deteriorate within 10,000 years in warm climates. In one case of optimal conditions — a cold, refrigerator-like cave — a human DNA sequence survived 430,000 years. These new findings show that proteins can last a lot longer.

More:
https://www.discovermagazine.com/planet-earth/our-ancestors-chipped-teeth-are-taking-scientists-further-back-in-time-than?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+DiscoverHumanOrigins+%28Discover+Human+Origins%29