DNA of remains found by U of A researcher sheds light on human activity in Africa 20,000 years ago

During an archeological dig in Tanzania in 2010, Elizabeth Sawchuk, then a 24-year-old University of Alberta master's student, uncovered a human skull dating back 18,000 to 20,000 years.

Never would the bioarcheologist imagine extracting DNA from such an ancient specimen, as the technology didn't exist at the time, let alone publishing a scientific paper on her findings more than a decade later. 

"If you had told me at the time that I would be talking to you 12 years later about her DNA, I wouldn't have believed you," Sawchuk told CBC's Edmonton AM on Tuesday. 

"It seemed like a long shot but I'm glad that we persevered and our team was able to extract the DNA because it's given us a completely new perspective on the past," she said.

"This individual is now the most ancient DNA we have from all of Africa."

Sawchuk, alongside 43 other scientists from 12 countries, published their research on the DNA of ancient individuals in the scientific journal, Nature on Feb. 23.

The research opens a black box in archeology, understanding how people interacted with one another during the last ice age, she said. 

"About 50,000 years in Africa, there's this big change in the archeological record. People start acting kind of more human. They start wearing art, they start making jewelry, they start using new and better types of stone and bone tools," she explained. 

Researchers also found evidence of long-distance social networks, meaning people not only traveled around sub-Saharan Africa but also had children with people who lived far from where they were born, she said.

They formed new alliances and trade networks. 

"That really helps us understand how when times get tough, humans get creative and it's given us a lot to think about," she said. 

When Sawchuk found the skull, they could only identify the age of the bones by carbon dating ostrich eggshell beads buried alongside the remains. 

It wasn't until 2015, when technology allowed scientists to extract genetic material of remains found in such hot and humid environments.

"It kind of was a game changer," Sawchuk said.