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The big news is, the fossil could also contain the holy grail of all primordial fossils: DNA.
18 Maret 2016 11:06
Brilio.net/en - Its largely known that motherhood will save the world and in this case, the dinosaurs world. A recently discovered pregnant Tyrannosaurus rex is shedding light on the evolution of ancient egg-laying creature as well as on gender distinction.
But the big news is, the fossil could also contain the holy grail of all primordial fossils: DNA.
According to Discovery News, assistant research professor of biological sciences at North Carolina State University Lindsay Zanno says yes, its possible, about the DNA or genetic materials that might be contained in the pregnant T-rex as well as similar dinosaur remains.
The T-rex, which was found in Montana and dates to 68 million years ago, has kept its medullary bone that reveals that the animal was pregnant. Medullary bone is only present in female living dinosaurs just before and during the egg-laying time and this one possibly retain preserved DNA.
Zanno, who is also head of the North Carolina Museum of Natural Sciences' Paleontology Research Lab and is a curator of paleontology explains that bone lines the marrow cavity of the long bones of birds.
Image vianews.ncsu.edu
"It's a special tissue that is built up as easily mobilized calcium storage just before egg laying," she said. "The outcome is that birds do not have to pull calcium from the main part of their bones in order to shell eggs, weakening their bones the way crocodiles do."
As largely known, crocodiles are the closest living sibling of dinosaurs.
"Medullary bone is thus present just before and during egg laying, but is entirely gone after the female has finished laying eggs," she said.
Zannos teammate Mary Schweitzer suspected that medullary bone was present in the tyrannosaur remains, and was able to confirm her suspicions after she, Zanno and their team conducted a chemical analysis of the T. rex's femur.
The material, which is found to be similar with medullary tissues from ostriches and chickens, contained keratan sulfate, a special substance not found in any other bone types.
"This analysis allows us to determine the gender of this fossil, and gives us a window into the evolution of egg-laying in modern birds," Schweitzer said.
According to Zanno, her team of scientists now know that extinct dinosaurs inherited egg laying from their ancestors, just as birds inherited this reproductive strategy from their dinosaurs ancestors.
"The discovery of medullary bone is just one more piece of evidence that blurs the line between birds and another theropod (carnivorous two-legged) dinosaurs like T. rex," she said.
The research is published in Nature Scientific Reports.
In an earlier study, Sarah Werning of the University of California and Berkeley and her team found a medullary bone in an Allosaurus, kind of carnivorous dinosaur. They also found the same bone in a Tenontosaurus, plant-eating dinosaur. These discoveries was found by chance, as she and the team were studying dinosaur growth rates when they realized three of the dinosaurs were pregnant females.
We were lucky to find these female fossils. Medullary bone is only around for three to four weeks in females who are reproductively mature, so you'd have to cut up a lot of dinosaur bones to have a good chance of finding this, she said.
Schweitzer agrees and said that the femur her team studied was already broken when she received it. She knows that most paleontologists are reluctant to cut open or demineralize their fossils in order to search for the rare medullary bone.
As the complete pregnant T-rex skeleton (including the skull) was discovered, theres a great chance to reveal a detailed description about its overall anatomy and general appearance. Its known that mom-to-be T-rex was 16-20 years old when she died. However, the cause of death is still to be investigated.
Source: Mashable
