Scientists destined in Africa have unearthed 3.8 million-year-old protein fragments preserved in an ostrich eggshell. The data found in this protein is found to be millions of years older than the oldest known DNA ever recovered. This significantly proves that recovering ancient proteins is possible even of extinct animals and human species.
This breakthrough changes the way ancient proteomics and paleontology views recovery of the building blocks of life since it seemed unlikely to do so before. Proteins are one of the basic building blocks of life that are expressed by the DNA. It comprises every bit of a living thing's body from the smallest parts like teeth, hair, and toenails to the biggest organs like skin and internal body organs. Study lead author Matthew Collins from York University said that they found the 3.8-million-year-old ostrich eggshell in Laetoli, Tanzania.
After analysis of the protein, the found the sequences to be much older than the oldest known DNA extracted from fossils, which was dated back to 700,000 years ago. The discovery led to the possibility that scientists may be able to recover proteins from the earliest humans. They believe the oldest traces of human habitation in Laetoli went as far as 3.75 million years ago. Proteins may not be as detailed as DNAs, but it can still express a lot about an organism.
The co-author and anthropologist Terry Harrison from New York University said the ancient proteins obtained from the enamel of teeth fossil may "yield important clues to the evolutionary relationships, species identity, sex, and migration patterns of early human ancestors."
The preservation of the "entrapped" proteins in the ostrich eggshell was made possible with the protection of surface minerals. The researchers raised a theory that is now tested if true. They think that it is possible to extract full or complete protein sequences from solid surfaces like bones, enamel, and egg shells - which is proven to be right after all. The team used computer models to visualize how the protein sequences managed to survive longer. Stabilization happened as the protein sequences bind strongly to surface minerals found on the hard object.
The researchers are excited to translate their findings to other old fossils like dinosaur eggshells that may now be the next interest for analysis, as reported by BBC.
Even though proteins do not hold as much information as DNA does, it may reveal genetic information 50 times older than DNA. This means proteins tend to degrade much slower than DNA making it a good source of ancient information. When the team isolated the entire protein sequences, rather than a single sequence, there will be able to determine the biological function of that protein encoded in the DNA.
The complete study was published in eLife.