[From _The New York Times_, July 1, 1993]
CELLS OF DINOSAUR APPARENTLY FOUND
Scientists Believe Blood Cells
in Tyrannosaurus Rex May
Lead to Traces of DNA
By MALCOLM W. BROWNE
A Montana paleontologist and his colleagues believe they have found
red blood cells in the fossilized leg bone of a Tyrannosaurus Rex
and say they have high hopes of extracting DNA from the dinosaur’s
The discovery of the putative dinosaur blood cells has not yet been
submitted to a scientific journal or independently confirmed but was
reported two weeks ago by the National Science Foundation, which has
financed the exploratory project. Jack Horner, a paleontologist at
Montana State University who directed the investigation, said in an
interview yesterday that his group hoped to find matches between
gene fragments left in the preserved blood cells with comparable DNA
segments from modern crocodiles or birds.
“If we’re lucky enough to find matches,” he said, “they could go a
long way toward showing what the relationship between dinosaurs and
birds might be. We’re not there yet, but we think we’re getting
The femur, or leg bone, that Mr. Horner’s group is studying is part
of an unusually well-preserved tyrannosaur fossil, more than 65
million years old, which they found and excavated from the Hell
Creek Formation in eastern Montana three years ago. The apparent
blood cells were discovered by Mary Schweitzer, Mr. Horner’s
graduate student who was investigating the cell structure of
fossilized bone and marrow tissue.
New Climate of Belief
In the past, few paleontologists or molecular biologists believed
that biological material could survive for millions of years without
becoming mineralized, thus losing its organic molecular structure.
The survival of any intact DNA, which ordinarily decays with time,
seemed even less likely. But the recent discovery of organic
material and even fragments of DNA in ancient plant and animal
fossils has changed opinions.
“Two years ago I would have called this baloney,” said Dr. Raul J.
Cano of California Polytechnic State University at San Luis Obispo,
a molecular biologist who has himself extracted DNA fragments from
fossilized insects and plants millions of years old.
Told of Mr. Horner’s belief that blood cells have survived in a
tyrannosaur bone – and that they may contain dinosaur DNA fragments
– Dr. Cano said: “It’s certainly plausible. We have seen similar
things ourselves, and there are reports from other investigators of
the finding of surviving biological material inside fossil dinosaur
bones, especially in the deep bone cortex, which seems to be
somewhat protected from mineralization.”
Earlier this month, Dr. Cano and his associates reported in the
British journal Nature that they had extracted DNA from a weevil
that had been entombed in amber for 120 million to 135 million
Doubter Grants Possibility
A molecular biologist who has strongly questioned the premise that
appreciable quantities of DNA could survive for very long periods is
Dr. Russell Higuchi of Roche Molecular Systems in Alameda, Calif.
But Dr. Higuchi said yesterday that it seemed possible that Mr.
Horner’s group, had actually seen dinosaur blood cells.
Although Dr. Higuchi said he remained doubtful about the survival of
dinosaur DNA, particularly in a fossil that was probably exposed to
water, “we ourselves speculated 10 years ago that if dinosaur DNA
survived at all, it might be found” deep inside a fossil bone.
Mr. Horner said that microscopic examination of a thin slice through
the dinosaur bone revealed that although its outer layers were
mineralized the bone itself, brown in color, remained more or less
intact in the interior of the marrow cavity.
“Mary found spherical structures that appear to be nucleated red
cells inside the blood vessels running through the bone, right where
you’d expect to find blood, if it’s there,” he said. “Since then
we’ve been trying everything we can think of to show that they’re
not blood cells, but they still seem to be the real thing.”
Fears of Contamination
Part of the science foundation’s grant to Mr. Horner’s group went
for laboratory equipment to conduct a polymerase chain reaction, a
technique that can single out a lone molecular fragment of DNA and
make enough copies so it can be analyzed using standard methods.
“The biggest problem is contamination of the fossil by foreign DNA,
“Mr., Horner said. “There’s lots of it there, The real trick is in
identifying something that is not a contaminant. This is why we are
looking for matches with crocodile DNA, which is not a likely
Mr. Horner says he is certain that at least some original tissue
remains in the fossil because his group has positively identified
collagen in the bone. Collagen is a fibrous protein found in the
connective tissue of animals, which ordinarily decays rapidly except
under special circumstances.
Cheryl Dybas, a spokeswoman for the National Science Foundation,
acknowledged that her agency had intentionally released its report
of Mr. Horner’s progress to coincide with the opening of “Jurassic
Park,” a science fiction movie based on the premise that dinosaurs
might one day be cloned from their surviving DNA.
“We thought it would be a good opportunity to get the word out on 4
of the 10 dinosaur research projects the N.S.F. is funding this
year, including that of Mr. Horner,” Ms. Dybas said.