This is pretty cool stuff.
Jurassic Park Redux?
Scientists May Have Cells
From a Dinosaur
March 25, 2005; Page B1
As Bob Harmon hunted for dinosaurs in the Hell Creek Formation in north-central Montana in the summer of 2000, he hadn’t a clue that what he was about to find would produce a bombshell with “Jurassic Park” overtones.
The rugged region was living up to its infernal name. Mr. Harmon, a fossil preparator at the Museum of the Rockies in Bozeman, Mont., had hiked into a steep box canyon when he noticed he was somewhere between stuck and lost. Sitting on the cliff side to eat a sandwich and plot his escape, he noticed a foot bone sticking out of the rock above him and instantly recognized that it was the metatarsal of a Tyrannosaurus rex. He found his way out, trekked miles to the dig’s camp, grabbed a folding chair, hiked back, balanced precariously on the seat, and dug out the bone.
Lucky thing Mr. Harmon got lost that day, and not only because the smallish T. rex he found is now known around the museum as B. (for Bob) rex: This T. rex is unique in the annals of dinosaur finds. In today’s issue of the journal Science, researchers report that its thigh bone contains soft tissues, such as blood vessels and bone cells. Such life-like tissue, let alone cells, had never before been recovered from a dinosaur.
“Our theories of how fossils are preserved don’t allow for this,” says Mary H. Schweitzer of North Carolina State University, Raleigh. The soft tissues she extracted from the rex “contain microstructures which look like cells and are preserved in every way. Preservation to this extent has never been noted in dinosaurs before.”
Prof. Schweitzer is coy about whether “preserved in every way” includes the cells’ DNA, which is what the antiheroes of “Jurassic Park” used to clone a theme park full of dinos. But the flexible, hollow blood vessels she extracted contain small spheres and ovals that may be nuclei of endothelial cells, which line blood vessels. Cell nuclei contain DNA. Has she found any?
“We’re doing a lot in the lab that seems promising,” she says. Such as? “I don’t want to say.”
In the past, when scientists said soft tissue (anything other than bone) had been preserved through the eons, they meant that feathers or tissues of a dinosaur embryo, for instance, had been turned to stone in a process called mineralization. The form was preserved for eternity, but the condition was as different from the original, living version as a pillar of salt and Lot’s wife.
Mineralization, in other words, “doesn’t preserve soft tissue as soft tissue,” Prof. Schweitzer says. Instead, organic molecules are replaced with molecules of stone. In contrast, she says, “the tissues we isolated from the dinosaur bone are still soft and flexible.”
She and her colleagues used a bath of chemicals to dissolve the stony material in the marrow cavity of the rex’s thigh bone. (Yes, kids, you can try this at home: Drop a chicken bone in vinegar and let the hard stuff dissolve.) What remained after a week was a supple, stretchy material crisscrossed with branching blood vessels, as well as what looked like bone cells called osteocytes, some containing what looked like cell nuclei. With or without DNA is what the scientists won’t say.
Though it had all been dead for 68 million years, the tissue was similar in every way – down to the branching pattern of the blood vessels and the reddish-brown spheres that seemed to be cells – to that from an ostrich that had been dead for six months.
“The conventional wisdom has been that you can’t get residues like this after 10,000 years,” says paleontologist Kevin Padian of the University of California, Berkeley. “This really expands the realm of what is possible.”
Prof. Padian has himself studied “B. rex” – he and the museum’s Jack Horner determined, from the pattern of bone growth, that it was 16 to 20 years old at death – but wasn’t involved in the soft-tissue discovery. He is convinced that Prof. Schweitzer has indeed extracted once-living tissue from the rex’s thigh bone. “Mary is incredibly brilliant and careful,” he says. “When she does something she tests it six or seven different ways to eliminate any possible source of contamination.”
The astonishing finding suggests that paleontologists have been too pessimistic about what old bones might contain. The discovery of soft tissue in a 68 million-years-dead T. rex was partly serendipitous: The thigh bone was too big to fit into the helicopter back to the museum, so the scientists broke it in two, revealing the spongy inner core.
“Other very dense bone might preserve this kind of soft tissue,” including the bones of horned dinosaurs such as triceratops, Mr. Horner says. “I think other labs will start finding things like this if they open up their bones, too.” Prof. Schweitzer already has extracted translucent blood vessels from two other tyrannosaurs, and what look like osteocyte cells from two tyrannosaurs and a duck-billed hadrosaur.
By drawing once-living tissue out of the T. rex, scientists hope to figure out what the big guy was made of, whom he is related to as ancestor or descendant, how fast he grew and other particulars. Of course, Prof. Padian jokes, scientists will really be able to figure out how T. rex lived “once Jack and Mary clone him.”