‘DNA’ found preserved in 75-million-year-old dinosaur fossils for the first time

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Cartilage cells, chromosomes and DNA have been found preserved in the 75-million-year-old fossils of a baby duck-billed dinosaur, a study has claimed. Pictured, Hypacrosaurus cartilage seen under a microscope, showing individual cells, cell nuclei and inter-cellular bridges


Cartilage cells, chromosomes and DNA have been found preserved in the 75-million-year-old fossils of a baby duck-billed dinosaur, a study has claimed.

Researchers analysed the skull fragments of young, nest-bound Hypacrosaurus specimens unearthed from the ‘Two Medicine Formation’ in Montana in the US.

Experts have conventionally believed that such organic material should not be able to remain intact for so long — with DNA expected to only last under 1 million years. 

If the findings are correct, however, it would appear that organic material can survive for far longer than previously thought.

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Cartilage cells, chromosomes and DNA have been found preserved in the 75-million-year-old fossils of a baby duck-billed dinosaur, a study has claimed. Pictured, Hypacrosaurus cartilage seen under a microscope, showing individual cells, cell nuclei and inter-cellular bridges

Experts have long believed that such organic material should not be able to remain intact for so long — with DNA expected to only last under 1 million years. Pictured, top, the Hypacrosaurus fossils under increasing magnification, with Emu bones, bottom, for comparison

Experts have long believed that such organic material should not be able to remain intact for so long — with DNA expected to only last under 1 million years. Pictured, top, the Hypacrosaurus fossils under increasing magnification, with Emu bones, bottom, for comparison

‘These new exciting results add to growing evidence that cells and some of their biomolecules can persist in deep-time,’ said paper author and palaeontologist Alida Bailleul of the Chinese Academy of Sciences.

‘They suggest DNA can preserve for tens of millions of years.’

‘We hope that this study will encourage scientists working on ancient DNA to push current limits and to use new methodology in order to reveal all the unknown molecular secrets that ancient tissues have.’ 

In their study, Dr Bailleul and colleagues studied fossilised skull fragments of the young Hypacrosaurus under the microscope — finding exquisitely preserved cells within calcified cartilage tissues.

Two of the cartilage cells were still linked by an inter-cellular bridge — just as would be seen near the end of the process of cell division — while elsewhere cell nuclei could be seen as a dark material in the specimens.

One cartilage cells even held preserved dark elongated structures that the researchers believe may be chromosomes.

‘I couldn’t believe it, my heart almost stopped beating,’ Dr Bailleul said. 

If the researchers' findings are correct, it would appear that organic material can survive for far longer than previously thought. Pictured: left, two dinosaur cartilage cells in the late stages of cell division, centre, an individual cell and, right, a cell being tested for DNA. The red stain in the cell indicates the potential presence of preserved dinosaur DNA

If the researchers’ findings are correct, it would appear that organic material can survive for far longer than previously thought. Pictured: left, two dinosaur cartilage cells in the late stages of cell division, centre, an individual cell and, right, a cell being tested for DNA. The red stain in the cell indicates the potential presence of preserved dinosaur DNA

'These new exciting results add to growing evidence that cells and some of their biomolecules can persist in deep-time,' said paper author and palaeontologist Alida Bailleul of the Chinese Academy of Sciences. Pictured, a fossil Hypacrosaurus youngling (stock image)

‘These new exciting results add to growing evidence that cells and some of their biomolecules can persist in deep-time,’ said paper author and palaeontologist Alida Bailleul of the Chinese Academy of Sciences. Pictured, a fossil Hypacrosaurus youngling (stock image)

In their study, Dr Bailleul and colleagues studied fossilised skull fragments of the young Hypacrosaurus under the microscope — finding exquisitely preserved cells within calcified cartilage tissues. Pictured, an artist's impression of a Hypacrosaurus

In their study, Dr Bailleul and colleagues studied fossilised skull fragments of the young Hypacrosaurus under the microscope — finding exquisitely preserved cells within calcified cartilage tissues. Pictured, an artist’s impression of a Hypacrosaurus

Having made this remarkable discovery, the researchers next set out to see if original molecules might also be preserved in the dinosaur cartilage — using another specimen from the same dinosaur nesting ground.

The team found that the organic material surrounding the cells reacted to antibodies of so-called Collagen II, the dominant protein in the cartilage of vertebrates.

‘This immunological test supports the presence of remnants of original cartilaginous proteins in this dinosaur,’ said paper author and palaeontologist Mary Schweitzer of the North Carolina State University. 

Researchers analysed the skull fragments of young, nest-bound Hypacrosaurus specimens unearthed from the 'Two Medicine Formation' in Montana in the US. Pictured, an artist's impression of the dinosaurs' nesting ground

Researchers analysed the skull fragments of young, nest-bound Hypacrosaurus specimens unearthed from the ‘Two Medicine Formation’ in Montana in the US. Pictured, an artist’s impression of the dinosaurs’ nesting ground

Another test suggested that the fossils may also even contain some original fragments of dinosaur DNA.  

These findings fly against conventional scientific understanding, which maintains — based on modelling and experimentation — that DNA likely cannot last for a million years, let alone tens of millions of years.

The full findings of the study were published in the journal National Science Review.

WHY DID THE DINOSAURS GO EXTINCT?

Dinosaurs ruled and dominated Earth around 66 million years ago, before they suddenly went extinct. 

The Cretaceous-Tertiary extinction event is the name given to this mass extinction.

It was believed for many years that the changing climate destroyed the food chain of the huge reptiles. 

In the 1980s, paleontologists discovered a layer of iridium.

This is an element that is rare on Earth but is found  in vast quantities in space.  

When this was dated, it coincided precisely with when the dinosaurs disappeared from the fossil record. 

A decade later, scientists uncovered the massive Chicxulub Crater at the tip of Mexico’s Yucatán Peninsula, which dates to the period in question. 

Scientific consensus now says that these two factors are linked and they were both probably caused by an enormous asteroid crashing to Earth.

With the projected size and impact velocity, the collision would have caused an enormous shock-wave and likely triggered seismic activity. 

The fallout would have created plumes of ash that likely covered all of the planet and made it impossible for dinosaurs to survive. 

Other animals and plant species had a shorter time-span between generations which allowed them to survive.

There are several other theories as to what caused the demise of the famous animals. 

One early theory was that small mammals ate dinosaur eggs and another proposes that toxic angiosperms (flowering plants) killed them off.  



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