‘Preserved to the cellular level’: Paleontologists believe they found DNA in the fossilized remains of a dinosaur in China

Posted:

October 2, 2021 11:45 GMT

According to the researchers, the fossil’s preservation is “exceptional” due to the fine volcanic ash that buried the remains and preserved them “down to the cellular level.”

A group of paleontologists have published in the scientific journal Nature Communications Biology a study They claimed to have discovered biomolecules in the remains of a dinosaur that lived during the Lower Cretaceous period, between 113 and 125 million years ago.

The fossil was found in Liaoning Province, northeast China, and consisted of a femur of “Caudipteryx”, a turkey-feathered dinosaur.

Paleontologists placed the cartilage of the femur under a microscope and dyed it with hemoxylin and eosin, chemicals that have the property of accentuating cell nuclei and cytoplasm.

In parallel, they stained the cartilage of a modern chicken and found that both lit up in the same way. According to the study’s authors, the nuclei and chromatin, the material that makes up chromosomes, were visible in the dinosaur’s cartilage.

Li Zhiheng, co-author of the research, to explain That the preservation of the fossil was “exceptional” due to the fine volcanic ash that buried the body and preserved it “down to the cellular level”.

However, other members of the scientific community are not sure about the reliability of the results of this experiment. Until now , Oldest DNA The sequence belongs to a woolly mammoth just over a million years old that has been lying under a protective layer of Siberian permafrost since its death. Experts like Evan Saita, of the Center for Integrative Research at the Field Museum of Natural History in Chicago, argue that it is impossible to preserve dinosaur DNA to this day, given that their fossils are “ridiculously older” than those of the woolly mammoth.

Saita believes that what interacted with the chemicals in Caudipteryx’s cartilage were not biomolecules, but possibly microbes that settled in the mineralized filling of space vacated by the degraded genetic material.

This view is also shared by Nick Rawlins, director of the Paleogenetics Laboratory at the University of Otago in New Zealand.

“While the fossilized cells and DNA in this new dinosaur may resemble those of modern chicken, it is a stone version, in which cells and DNA have been replaced by minerals, in the same way that dinosaur bones are a mineralized version of bone” and pointed out.

For her part, palaeobiologist Love Dalin concluded that “the fact that different dyes or stains interact with bits of fossilized remains does not mean that any real molecule of DNA remains in the fossil.”