199 lines
8.6 KiB
Plaintext
199 lines
8.6 KiB
Plaintext
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(word processor parameters LM=8, RM=75, TM=2, BM=2)
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Taken from KeelyNet BBS (214) 324-3501
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Sponsored by Vangard Sciences
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PO BOX 1031
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Mesquite, TX 75150
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There are ABSOLUTELY NO RESTRICTIONS
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on duplicating, publishing or distributing the
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files on KeelyNet except where noted!
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July 5, 1993
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DINODNA1.ASC
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This EXCELLENT file shared with KeelyNet courtesy of Clark Matthews,
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of WRONG NUMBER BBS - 201-451-3063
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PO BOX 3934
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Jersey City, NJ
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07303-3934
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WRONG NUMBER FILE NAME: DINODNA1.ZIP
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[From _The New York Times_, July 1, 1993]
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CELLS OF DINOSAUR APPARENTLY FOUND
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Scientists Believe Blood Cells
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in Tyrannosaurus Rex May
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Lead to Traces of DNA
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By MALCOLM W. BROWNE
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A Montana paleontologist and his colleagues believe they have found
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red blood cells in the fossilized leg bone of a Tyrannosaurus Rex
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and say they have high hopes of extracting DNA from the dinosaur's
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cells.
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The discovery of the putative dinosaur blood cells has not yet been
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submitted to a scientific journal or independently confirmed but was
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reported two weeks ago by the National Science Foundation, which has
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financed the exploratory project. Jack Horner, a paleontologist at
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Montana State University who directed the investigation, said in an
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interview yesterday that his group hoped to find matches between
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gene fragments left in the preserved blood cells with comparable DNA
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segments from modern crocodiles or birds.
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"If we're lucky enough to find matches," he said, "they could go a
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long way toward showing what the relationship between dinosaurs and
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birds might be. We're not there yet, but we think we're getting
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close."
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The femur, or leg bone, that Mr. Horner's group is studying is part
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of an unusually well-preserved tyrannosaur fossil, more than 65
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million years old, which they found and excavated from the Hell
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Creek Formation in eastern Montana three years ago. The apparent
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blood cells were discovered by Mary Schweitzer, Mr. Horner's
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graduate student who was investigating the cell structure of
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fossilized bone and marrow tissue.
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Page 1
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New Climate of Belief
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In the past, few paleontologists or molecular biologists believed
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that biological material could survive for millions of years without
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becoming mineralized, thus losing its organic molecular structure.
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The survival of any intact DNA, which ordinarily decays with time,
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seemed even less likely. But the recent discovery of organic
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material and even fragments of DNA in ancient plant and animal
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fossils has changed opinions.
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"Two years ago I would have called this baloney," said Dr. Raul J.
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Cano of California Polytechnic State University at San Luis Obispo,
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a molecular biologist who has himself extracted DNA fragments from
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fossilized insects and plants millions of years old.
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Told of Mr. Horner's belief that blood cells have survived in a
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tyrannosaur bone - and that they may contain dinosaur DNA fragments
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- Dr. Cano said: "It's certainly plausible. We have seen similar
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things ourselves, and there are reports from other investigators of
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the finding of surviving biological material inside fossil dinosaur
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bones, especially in the deep bone cortex, which seems to be
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somewhat protected from mineralization."
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Earlier this month, Dr. Cano and his associates reported in the
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British journal Nature that they had extracted DNA from a weevil
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that had been entombed in amber for 120 million to 135 million
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years.
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Doubter Grants Possibility
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A molecular biologist who has strongly questioned the premise that
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appreciable quantities of DNA could survive for very long periods is
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Dr. Russell Higuchi of Roche Molecular Systems in Alameda, Calif.
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But Dr. Higuchi said yesterday that it seemed possible that Mr.
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Horner's group, had actually seen dinosaur blood cells.
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Although Dr. Higuchi said he remained doubtful about the survival of
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dinosaur DNA, particularly in a fossil that was probably exposed to
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water, "we ourselves speculated 10 years ago that if dinosaur DNA
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survived at all, it might be found" deep inside a fossil bone.
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Mr. Horner said that microscopic examination of a thin slice through
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the dinosaur bone revealed that although its outer layers were
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mineralized the bone itself, brown in color, remained more or less
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intact in the interior of the marrow cavity.
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"Mary found spherical structures that appear to be nucleated red
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cells inside the blood vessels running through the bone, right where
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you'd expect to find blood, if it's there," he said. "Since then
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we've been trying everything we can think of to show that they're
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not blood cells, but they still seem to be the real thing."
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Fears of Contamination
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Part of the science foundation's grant to Mr. Horner's group went
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for laboratory equipment to conduct a polymerase chain reaction, a
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technique that can single out a lone molecular fragment of DNA and
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make enough copies so it can be analyzed using standard methods.
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Page 2
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"The biggest problem is contamination of the fossil by foreign DNA,
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"Mr., Horner said. "There's lots of it there, The real trick is in
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identifying something that is not a contaminant. This is why we are
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looking for matches with crocodile DNA, which is not a likely
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contaminant."
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Mr. Horner says he is certain that at least some original tissue
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remains in the fossil because his group has positively identified
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collagen in the bone. Collagen is a fibrous protein found in the
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connective tissue of animals, which ordinarily decays rapidly except
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under special circumstances.
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Cheryl Dybas, a spokeswoman for the National Science Foundation,
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acknowledged that her agency had intentionally released its report
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of Mr. Horner's progress to coincide with the opening of "Jurassic
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Park," a science fiction movie based on the premise that dinosaurs
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might one day be cloned from their surviving DNA.
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"We thought it would be a good opportunity to get the word out on 4
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of the 10 dinosaur research projects the N.S.F. is funding this
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year, including that of Mr. Horner," Ms. Dybas said.
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WRONG NUMBER FILE NAME: DINODNA1.TXT
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Jerry W. Decker.........Ron Barker...........Chuck Henderson
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Vangard Sciences/KeelyNet
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Page 3
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