One of the world’s oldest species may provide the oldest genetic data ever recorded. A recent study show that protein fragments from the eggshells of ancient Ostriches may be 50 times older than any DNA discovered.
Previously, DNA fragments that had been frozen in Permafrost for 700,000 years were considered the oldest. Surprisingly, the hot and arid conditions of Tanzania, once thought to prohibit such finds, actually preserved the protein.
Professor Matthew Collins, of the University of Sheffield, who led the research team, says,
To date, DNA analysis from frozen sediments has been able to reach back 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.
Researchers on an archaeological dig discovered preserved fossil proteins in ostrich shells that were 3.8 billion years old. They analyzed Ostrich eggshell fossils from Tanzania and South Africa. Computerized models showed that the protein survived the harsh conditions due to mineral bonding within the shell. The proteins that were isolated are struthiocalcin-1 and struliocalcin-2.
Ostrich shells are very thick and are able to survive many different environmental conditions.
Dr. Beatrice Demarchi of the University of York, who worked on the study says,
Evidence suggested that it was the more fluid, unstable region of the protein that promoted and regulated mineral growth in the shell, but was also less likely to survive over time and the intense heat of the African climate. 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.
The researchers hope that their data will give archaeologists the ability to target which fossils they choose to study.
Dr. Collin Freeman of the University of Sheffield, part of the research team, says,
Remarkably, the oldest eggshell in the study – from the famous 3.8 million year-old site of Laetoli in Tanzania – a region where the protein was still there, giving us a unique insight into what to look for when analyzing fossils of this kind. Now that we know minerals can trap and preserve proteins in this way, we can be more targeted in our study of ancient remains.