CNN
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Scientists are recovering ancient proteins from fossilized rhino teeth and breaking new ground in their studies of ancient life on Earth.
The 204 million-year-old teeth excavated in the Arctic Circle of Canada contain 10 times the oldest proteins of the ancient DNA. Using samples, scientists analyzed the oldest detailed protein sequences on record.
“They’re the ones who are leading Canadian researchers, Ryan Sinclair Patterson, a postdoctoral researcher at the Globe Institute at the University of Copenhagen, Denmark, who leads research in Canada. “It’s essentially a safe. At least for this particular fossil, what we did was unlock this safe.”
Research into ancient DNA, preserved in bones, fossils and dirt, revolutionised archaeological science, bringing back curtains of lost empires, mystical clans, ice age creatures, and previously unknown human species. Ancient proteins promised a similar revolution in fossils millions of years ago, and now go beyond the chronology of ancient DNA.
The study was published in the scientific journal Nature on July 9th and presents the great potential of a field known as Paleproteomics.
Proteins consist of amino acid sequences are more robust than DNA, a fragile molecule that breaks down relatively easily. Proteins contain little detailed information, but in some cases even the gender of a fossil can help unravel the evolutionary history of the specimen, diet.
“The next step is to demonstrate that it’s not just a sample, it’s a lucky strike,” said co-author Enrico Capellini, a professor at the Globe Institute at the University of Copenhagen, who is the professor who extracted proteins from fossils and pioneered the methods that have been involved in Canadian research.
“But potentially there is a huge field of research that can be made clearer and if you actually push it further… you can even begin investigating dinosaurs,” he added.
Cappellini and Paterson, along with colleagues from York University and the Canadian Natural Museum, recovered sequences from seven proteins preserved in fossilized rhino teeth.
The sequence of ancient proteins involves determining the order of amino acids in a sample. Scientists were able to gather information about rhino evolution by comparing them with sequences of living relatives and extinct relatives. Analysis reveals that it diverged from the same family as the rhinoceros living around 41 to 25 million years ago.
“The fossil record had some crazy shapes (of rhinoceros species). I’ve heard of Siberian unicorns with wool rhinos and probably huge horns,” Patterson said. “What we can do is compare mystery rhinoceros with other forms and find out where they are in the family tree.”
Separate studies published on July 9 in Nature, a journal sampling of fossils from the Turkana Basin, Kenya, suggest that even tropical environments where biomolecules are burnt can survive for millions of years.
This study, which analyzed 10 mammal fossils, including today’s elephants, hippos, and rhino parents, was published by researchers at the Smithsonian Institute of Museum Conservation and Harvard University.
They recover proteins from five fossils from 1.5 million to 18 million years ago, and found that even in hot tropical regions, scientists can extract prehistoric proteins.
The information contained in Kenya proteins was less detailed than that found in Canadian fossils, but the authors said that their presence within enamel tissues in one of the warmest regions of the world has the promise that much older fossil proteins can be discovered.
“We were an exciting success. We’ve returned to about 18 million years. I think we can go back in time,” said Timothy Cleland, a physical scientist at the Museum Conservation Institute.
Research into Canadian fossils is “sounding and very interesting,” said Marten DeHainens, a researcher at the University of Ghent in Belgium, who specializes in proteomics. However, Dhaenens, who was not involved in either study, said the methodology used in Kenya’s fossils was complex and less tested. He argued that the researchers’ findings are difficult to interpret and guarantee a more thorough assessment.
“The data is public so we should be able to verify their claims through manual verification, but this will take some time,” he said in an email.
Evan Sita, a paleontologist and researcher at the Museum of Natural History of Chicago, said it was “shocking” to find proteins preserved within fossils at tropical latitudes, adding that the findings require replicating. It was assumed that cold temperatures would be needed to slow protein breakdown.
“If that’s the real result…it should be very easy to replicate,” he pointed out. “We should be able to travel around every different fossil site around the world and find enamel peptides (proteins).”
Getting proteins from these old fossils would be a realization of paleontologists’ dreams, said Matthew Collins, a MacDonald professor of paleontology at the University of Cambridge in the UK, agreed that research into Canadian fosils is more convincing. Collins, like Saitta, was not involved in new research.
“This is amazing. It’s really exciting, but at the same time, I was very disappointed in my career, thinking we had very old proteins and didn’t,” added Collins, who tried to retrieve proteins from dinosaur fossils.
Collins and Saitta were part of a team that detected amino acids in titanosaurus eggshell fragments, according to a study published in 2024. The eggs were born 66 million years ago by a plant-eating sauropod, a giant, long-necked dinosaur that lived in the late Cretaceous period, just before the dinosaurs had disappeared.
However, dinosaur eggshells did not have an identifiable protein sequence. Their results resemble the five-letter identification in the novel, revealing only a pattern of decay that showed that once there was protein in the eggshell, Saita said.
“There’s no remaining sequences or information. Just a small, individual LEGO building block of (amino acids),” Collins said.
Retrieving protein information from dinosaur teeth is a long shot, and Saitta noted that he gave up in search of dinosaur fossil proteins and exploring more interesting research questions.
He pointed out that dinosaur fossils are not only far older than fossils in two studies, but can also be traced back to the time of the world’s climate borough when there was no ice hat. Furthermore, on average, dinosaur fossils are buried much deeper, resulting in much greater geothermal heat. It is also not clear whether dinosaur teeth are thick enough enamel to store proteins, he added.
Cappellini and Paterson said it may be possible to retrieve useful protein information from dinosaur fossils within ten years, but there were other interesting questions to investigate first, such as how mammals came to control the planet after the dinosaur’s end.
“I really think some sites may store dinosaur proteins at a deep time. Maybe we can give them to the shot,” Patterson said.
