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Old post on _T._rex_ red blood cells




To John Rafert, et. al.:

John Matrow uploaded this document to the Dinosaur 
list on Thursday, July 8 09:06:44 1993:

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Is Dinosaur DNA More Than Stuff of Movies?
By Malcolm W. Brown
New York Times Service
July 1, 1993

      A Montana paleontologist and his colleagues think 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 cells.
      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 project.
      Jack Horner, a paleontologist at Montana State University
who directed the investigation, said Wednesday 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 close."
      Cheryl Dybas, a spokeswoman for the National Science
Foundation, acknowledged that her agency had intentionally
released its report of 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.
      The femur, or leg bone, 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 Schwietzer, Horner's graduate
student, who was investigating the histology, or cell structure,
of fossilized bone and marrow tissue.
      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 Raul
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.
     "It's certainly plausible," Cano said. "We have seen similar
things ourselves." Earlier this month Cano and his associates
reported in the journal Nature that they had extracted DNA from a
weevil that had been entombed in amber for 120 million to 135
million years.
     Molecular biologist Russell Higuchi, who has strongly
questioned the premise that appreciable quantities of DNA could
survive for eons, said Wednesday that it was possible that
Horner's group has actually seen dinosaur blood cells.
     "We ourselves speculated 10 years ago that if dinosaur DNA
survived at all, it might be found" deep inside a fossil bone,
said Higuchi, of Roche Molecular Systems in Alameda, Calif.
     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.
     Part of the science foundation's grant to Horner's group
went for laboratory equipment to conduct a polymerase chain
reaction, a technique that can single out a lone molecule
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," 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 contaminant."

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 Douglas E. Goudie                  To know all things is not permitted.
 ac941@leo.nmc.edu                               -- Horace (65 - 8 B.C.)