Scientists in China May Have Found 125-Million-Year-Old Dinosaur DNA
The idea that scientists might be able to recover dinosaur DNA from fossilized remains seems absurd. But now, the concept has moved beyond the realms of the absurd to the absolutely possible, thanks to the incredible work of a team of paleontologists from China.
From inside the fossilized leg bone of a small, peacock-like dinosaur that roamed the earth 125 million years ago, these scientists discovered remarkably well-preserved cartilage cell specimens, which still maintained a surprising level of structural integrity. Some of the cells still retained their nuclei, and one even contained attached samples of other organic molecules, including chromatin. The latter is a substance found inside cells that is constructed entirely from tightly packed dinosaur DNA particles.
Could there be actual dinosaur DNA preserved inside the cell nuclei and/or chromatin? If so, could it be sequenced, to produce accurate models of dinosaur DNA? While scientists are a long way from accomplishing this at the present moment, the discovery of cellular material known to contain DNA in unimaginably ancient dinosaur fossils raises some brand new and highly exciting possibilities.
The Chinese scientists have been able to detect cartilage cells from the fossilized remains of a small Caudipteryx dinosaur. This could enable them to recover and sequence dinosaur DNA. (Elenarts / Adobe Stock)
Could Fossilized Dinosaur DNA Be Recovered and Sequenced? Perhaps!
The scientists involved in this groundbreaking research project were affiliated with the Chinese Academy of Science’s Institute of Vertebrate Paleontology and Paleoanthropology (IVPP), and with the Shandong Tianyu Museum of Nature. As they explain in an article in the journal Communications Biology, they were able to detect and isolate the cartilage cells while examining the fossilized remains of a small dinosaur called Caudipteryx.
- World’s First Complete Dinosaur Skeleton Has Been Vividly Brought to Life
- Chinese Boy Accidentally Finds 66-Million-Year-Old Dinosaur Eggs
The Caudipteryx lived near the shores of shallow lakes that were once located in the Jehol Biota in the modern-day Liaoning province of northeastern China. Past studies have revealed this peacock-like creature, which possessed long tail feathers and many other avian characteristics, lived during the Early Cretaceous period, perhaps exclusively in China.
The Jehol Biota region is noted for producing dinosaur remains that are intact and in shockingly good condition. “Geological data has accumulated over the years and shown that fossil preservation in the Jehol Biota was exceptional, due to fine volcanic ashes that entombed the carcasses and preserved them down to the cellular level,” explained study co-author Zhiheng Li, an Associate Professor at the IVPP, in a Chinese Academy of Sciences press release.
Photograph of the dinosaur fossil (a), the location of the extracted fragment on the right femur (b) which could provide the dinosaur DNA, and line drawing of the dinosaur specimen (c). (Zheng, X. et. al. / CC BY 4.0)
Surprising, Miraculous and Exceptional Discovery of Cell Nuclei
Nevertheless, the discovery of cell nuclei in a fossil obtained from there is still quite surprising. “The preservation of cell nuclei in long extinct organisms is currently considered rare and exceptional,” the scientists wrote in their Communications Biology article. “Due to the fragility of nucleic acids, nuclei are thought to degrade extremely rapidly after death (sometimes within hours postmortem), leaving almost no chance for these structures to enter the fossil record.”
And yet, the scientists noted, on occasion the near-miraculous can and does happen. “The paleontological literature is full of histological reports of fossil tissues with exquisitely preserved nuclei and even sub-nuclear structures like nucleoli or chromosomes in multiple stages of cell division,” they wrote. “These examples are numerous and include nuclei from permafrost-preserved Cenozoic mammals, Mesozoic dinosaurs, various Cenozoic, Mesozoic, and Paleozoic plants, and even embryo-like fossil cell clusters that are more than 600 million years old.”
This is actually the second time in the last two years that nuclei and associated chromatin threads were found inside the fossilized remains of dinosaur cartilage cells. According to National Geographic, in a 2020 study scientists found such cells inside the fossilized skeleton of a duck-billed dinosaur, known as Hypacrosaurus stebingeri, which lived approximately 75 million years ago.
A microscope image of the Caudipteryx cells, including one with its purple-stained nucleus. (Zheng, X. et. al. / CC BY 4.0)
Have They Really Found Dinosaur DNA Inside Cell Nuclei?
This would seem to suggest cartilage cells possess unique characteristics that make them more likely to retain their nuclei and some additional organic materials even after fossilization begins. The scientists involved in the Chinese study found that the cells they discovered had been protected by a process known as silicification, whereby organic materials can be fossilized into silicate minerals.
The team believes that this silicification is what kept some of the cell nuclei in such a well-preserved state, allowing them to retain and display some of their “living” characteristics after they’d been decalcified and subjected to examination.
In this latest study, the scientists isolated groups of cells and stained them with a purple chemical known as hematoxylin, which can bind with the nucleus of a cell if the nucleus is there. During this activity, many nuclei were found in cartilage cells, and in one a purple-stained nucleus was observed that had some darker purple threads connected to it.
The scientists realized, much to their delight, that in this one cell an assortment of genetic material had been preserved, including various biomolecules and chromatin threads. Chromatin contains DNA, as does cell nuclei. If dinosaur DNA still exists inside these cellular remnants, it could eventually be extracted and decoded—it is hoped.
A lot of research and development work needs to be completed before scientists can accomplish this goal, however. “We are obviously interested in fossilized cell nuclei because this is where most of the DNA should be if DNA was preserved,” said study co-author Alida Bailleul, another Associate Professor from the IVPP. “So, we have good preliminary data, very exciting data, but we are just starting to understand cellular biochemistry in very old fossils. At this point, we need to work more.”
Unlocking the Hidden Secrets of Dinosaur DNA
While cell nuclei and associated materials have been detect inside ancient fossilized animal remains on several occasions, no one has successfully sequenced DNA from a sample that is more than one million years old. In truth, no one has really expected to be able to sequence dinosaur DNA, since it has always been presumed that their DNA would not have survived the fossilization process.
- World First: Dinosaur Found on Fossilized Eggs with Babies Inside!
- This Tiny Predator Existed Alongside the Giant Dinosaurs
But this new study from China suggests this may not be the case. If techniques are eventually developed that allow scientists to sequence dinosaur DNA, from the Caudipteryx sample or from any other fossils that might contain it, the science of paleontology would be changed forever.
Dinosaurs have been physically reconstructed from fossilized bones. The sequencing of dinosaur DNA could bring them more fully back to life, allowing scientists to learn more about their lives and lifestyles than anyone ever imagined would be possible.
Top image: Artists representation of the small Caudipteryx dinosaur specimen in the Jehol Biota, from which dinosaur DNA could be extracted. Source: Zheng Qiuyang
By Nathan Falde