New evidence suggests proteins can persist for much longer than previously thought, potentially offering scientists a deeper view of genetic history.

A team of researchers from Europe recently identified fossil proteins in a 3.8 million-year-old ostrich eggshell. The protein fragments -- or others like them -- could offer up genetic information 50 times older than the oldest DNA sample.

Until now, researchers assumed genetic material would be unable to survive the heat of southern Africa.

"To date, DNA analysis from frozen sediments has been able to reach back to about 700,000 years ago, but human evolution left most of its traces in Africa and the higher temperature there takes its toll on DNA preservation," lead researcher Matthew Collins, an archaeologist at the University of York, explained in a news release.

But Collins and his research partners had a theory that proteins might survive if attached to harder surfaces, like the mineral surface of an eggshell. The research team collected ancient eggshells from dig sites in Tanzania and South Africa.

"Remarkably, the oldest eggshell in the study -- from the famous 3.8 million year-old site of Laetoli in Tanzania -- a region of the protein was still there, giving us a unique insight into what to look for when analyzing fossils of this kind," said Colin Freeman, a materials and computer scientist at the University of Sheffield. "Now that we know minerals can trap and preserve proteins in this way, we can be much more targeted in our study of ancient remains."

Previous research suggested the more fluid yet unstable parts of proteins govern mineral growth in eggshells, but are less likely to survive. The latest research -- detailed in the journal eLife -- revealed the opposite.

"As we examined older and older eggshells, we could see that this assumption was surprisingly wrong, as it was in fact the unstable regions that survived the best," said York archaeologist Beatrice Demarchi. "They were able to bind more strongly to the eggshell, allowing it be preserved in time."

Ostrich eggshells are abundant at many archaeological and palaeontological sites in Africa. Early humans used the eggshells to carry water as well as a medium for art and jewelry. Further analysis of ancient ostrich eggshell proteins could yield insights into early interactions between humans and animals.