Fossil protein extracted from a 3.8 million-year-old ostrich eggshell fragment could open up a new frontier in archaeology, experts in Yorkshire have said.
The surprising survival of the protein suggests that ancient eggshell can yield genetic information almost 50 times older than any DNA record, say scientists.
Eggshell protein dating back millions of years could shed light on how the earliest humans lived, how they interacted with animals, and why some became extinct while others continued to evolve.
Ostrich eggs were widely used by the first humans and often found at archaeological sites in Africa.
They were employed as raw materials for creating works of art and jewellery, and for carrying water.
The egg shell is very thick and hard-wearing and survives under many different environmental conditions.
Lead researcher Professor Matthew Collins, from the University of York’s Department of Archaeology, said: “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.
“We had known for many years that proteins could give more clues into the past, but when we looked at protein decay in eggshells, it gave us unusual results when compared to other fossil materials and, until now, we have not really known why.”
The scientists found that parts of proteins bound strongly to surface minerals in the eggshell, allowing preservation over long stretches of time.
Ostrich egg shell fragments collected from Tanzania and South Africa were examined by the researchers.
Co-author Dr Colin Freeman, from the University of Sheffield, said: “Remarkably, (in) 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 analysing fossils of this kind.
“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.”
The research is published in the journal eLife.