Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.

DATE: MONDAY, May 31, 1993 TAG: 9305290221


In a couple of weeks, its promoters hope, crowds of dinosaur fans will pack theaters to watch "Jurassic Park," Steven Spielberg's $56 million dinosaur movie, the most ambitious Mesozoic-monster film ever made. Based partly on recent advances in microbiology, the movie's visual thrills and state-of-the-art animation may leave audiences gasping.

Scientists seem as eager as anyone else to see the highly publicized film, which incorporates some of the latest discoveries about the preservation of the DNA of extinct animals. But many microbiologists are critical of the movie's speculative premise that dinosaurs might one day be resurrected from the dead. Some scientists are also uneasy about what they perceive as an anti-science bias in the plot, a charge that the author himself acknowledges.

In its attack on biotechnology, they say, "Jurassic Park" revives the Frankenstein image of amoral scientists unleashing forces they cannot control. The cinematic re-creation of animals that have been extinct for 65 million years will enchant viewers, they argue, making the movie's anti-science message all the more potent.

Although the movie features a number of well-known stars, including Jeff Goldblum as a doom-saying mathematician and Sir Richard Attenborough as a billionaire Texas entrepreneur, the real stars are the dinosaurs themselves, re-created by the latest movie technology. The scientific gimmicks on which the story is based were thought up by real scientists who know something about the obstacles that would have to be surmounted to bring 80-million-year-old fossils back to life. Some of them also worked on the film as advisers to the model builders, robotics experts, artists and computer animators.

"Jurassic Park" is based on Michael Crichton's 1990 best seller of the same name, whose ingenious premise is that mosquitoes and flies back in the Mesozoic era (230 to 65 million years ago) must sometimes have drawn blood from dinosaurs before alighting on fresh tree resin and getting stuck and, ultimately, fossilized. After the dried resin hardened into amber, these insects -- and their last meals of blood, it is supposed -- were sometimes preserved so perfectly that they remained more or less intact down to the present day.

From the notion that preserved dinosaur blood may still exist in the bellies of amberized mosquitoes, it was just a short fictional hop (albeit a well-nigh impossible scientific leap) to cloned dinosaurs, mayhem and a best-selling thriller.

There is some dispute as to who first made the conjectural connection between bugs in amber and revivified dinosaurs, but there seems to be no question that Charles Pellegrino of Rockville Centre, Long Island, was the first to publish the idea. Pellegrino, a writer of science fiction and nonfiction, holds a Ph.D. in paleobiology, and has long been interested in insects in amber. In 1977, he was shown a fly that had been embedded in New Jersey amber for 95 million years, and it started a train of thought.

In the March 1985 issue of Omni, a magazine that blends real science with fiction, Pellegrino wrote, "Three more decades of technological advance and we may be able to extract and read DNA from the flies' stomachs, where, if we are lucky, we will find the blood and skin of dinosaurs."

Since flies flew among and occasionally drew their nourishment from dinosaurs, he went on, it is possible that scientists may one day publish the genetic codes of creatures known only from their bones and footprints.

Hatching a dinosaur

"If portions of the code are missing," he wrote, "we might conceivably figure out what belongs in the gaps and edit in the `paragraphs.' Perhaps we could borrow from currently living animals to provide a complete set of proteins necessary for the survival of the original dinosaur. Then everything that goes into building a dinosaur could be published in the form of chromosomes. We could insert these into a cell nucleus, provide a yolk and an eggshell, and hatch our own dinosaur."

Microbiologists regard this idea as wildly implausible, pointing out that no one has yet succeeded in cloning even a living animal with an intact genetic code, much less an extinct one whose genes have been mostly destroyed or damaged.

Russell Higuchi of Roche Molecular Systems Inc., in Alameda, Calif., a leading experts in genetic microbiology, recently circulated a condemnation of `Jurassic Park' to scientific colleagues. Both the book and movie, he wrote, contain "gross overstatements of the capabilities of DNA technology" that "lead to unreasonable fear" of it. According to this line of reasoning, hesaid, "If dinosaurs can be brought back to life, who knows what other evils gene technology may be capable of?"

Window Into Past

"Jurassic Park" would have been complete fantasy, had there not been some breathtaking scientific advances during the 1980s, one of the most startling of which was made by George Poinar Jr., an insect pathologist at the University of California at Berkeley. In 1962 Poinar was strolling along a stretch of Denmark's western coast when he discovered a chunk of amber that had washed ashore. Starting with that find, amber collecting became a hobby for Poinar.

Twenty years later it became his life work, and he now calls amber his
golden window" into the past.

That year, he and his wife, Roberta Hess, a microscopist at Berkeley's entomology department, acquired a fungus gnat embedded in amber that had been mined from a rocky sediment known to be 40 million years old, and they went to work on it. To start, the two scientists placed their amber chunk on the stage of an ordinary microscope, expecting to see little more than the outlines of the fossilized insect parts.

"Instead, we observed dark areas within the outline, indicating that the body of the organism itself, not an impression or a fossil, was inside the amber," Poinar recalled in last month's issue of The Sciences, a magazine published by the New York Academy of Sciences.

Moving their specimen to a vastly more powerful electron microscope, Poinar and Hess were amazed to find that they could clearly discern the gnat's muscle cells. They could see the nuclei, containing chromatin (which carries the cell's genes) and mitochondria, which provide a cell with its power. Mitochondria contain a special type of DNA, believed to descend only through the female line, which may be a useful indicator of an organism's evolutionary background.

The idea of extracting and analyzing DNA from mummified tissue was largely speculative at that time, but in 1984 another great technical achievement put the speculation on more solid ground. That year three biochemists at Berkeley -- Allan Wilson, Higuchi (who later joined Roche Molecular Systems) and Svante Paabo -- went to work on the preserved skin of an animal that had been extinct for 140 years.

Their subject was a quagga, a brown, horselike beast with zebra stripes on the front of its body, which inhabited South Africa until it was exterminated by hunters in the early 19th century. After cutting some samples from a quagga skin preserved in a German museum, the scientists managed to extract enough DNA from the animal's flesh to determine some of its sequences of "base pairs," the molecular rungs that link the two spiral halves of a DNA molecule.

Problems recovering DNA

The Berkeley group compared quagga DNA with comparable sequences from related animal species, and found that the quagga was only distantly related to the common horse and was a much closer kin to the modern plains zebra. Wilson and his colleagues thus settled an old zoological argument about the antecedents of the quagga, but more important, they demonstrated that it is possible to make useful discoveries from old DNA.

Unfortunately, such specimens rarely contain much recoverable DNA; there is generally far too little of it left to analyze, and what little there may be is usually badly degraded. But in 1985, biochemists at the Cetus Corporation in Emeryville, Calif., invented and patented a process that has revolutionized microbiology and the study of DNA. Called the polymerase chain reaction (PCR), it can take a selected piece of a DNA molecule and make trillions of exact copies in a matter of hours -- enough for a scientist to analyze.

Once PCR was available, biologists began exploring the genetic codes of all kinds of fossil and mummified material containing only the faintest traces of DNA -- 17-million year-old fossil leaves, ancient Andean corn, flightless New Zealand birds, a 40,000-year-old mammoth, the mummified brains of 7,500-year-old Florida Indians and much more.

Last year two research groups independently recovered and analyzed fragments of insect DNA some 40 million years old, not quite as old as the dinosaurs (which died out 65 million years ago), but very old indeed.

One group, headed by Poinar and including his son Hendrik, and Raul Cano of California Polytechnic Institute and David Roubik of the Smithsonian Institution, got their DNA from a 40-million-year-old extinct stingless bee found in amber mined in the Dominican Republic. The other group, Rob DeSalle, Ward Wheeler and David Grimaldi of the American Museum of Natural History in New York, and John Gatesy of Yale University, worked on Dominican amber containing an extinct termite.

The museum's analysis of the termite's DNA challenges a prior belief that termites evolved from cockroaches; its DNA suggests that termites and roaches evolved independently of each other, from some common ancestor.

Novelist enters picture

While all this is fascinating science that has greatly enlivened professional meetings and journals, it falls hopelessly short of bringing dinosaurs back to life. Still, fiction can always find a way. Enter Michael Crichton.

Crichton, the author of "The Andromeda Strain" and other popular science novels and screen plays, holds a medical degree, as did Sir Arthur Conan Doyle. "We're both failed doctors who found storytelling more congenial than healing," he said in a recent interview. "Sometimes I think I've devoted my life to rewriting Conan Doyle in different ways."

Both the book and the movie draw from the work and personality of Jack Horner, the Montana paleontologist who discovered that some dinosaurs apparently looked after their young in colonies, rather than merely laying eggs and abandoning them. Besides serving as a model for one of the characters in the book, he later worked as an adviser to the movie makers on dinosaur musculature and movement, and on the appearance of real field laboratories. In return, Horner and his Montana colleagues have been promised research support from Spielberg's Amblin organization.

Microbiologists view "Jurassic Park" as a veiled attack on science, and Crichton himself acknowledges an anti-scientific undertone in most of his novels, including "Jurassic Park." "I'm surprised more people haven't noticed it more than they have," he said in an interview. "I'm enthusiastic about science, but there is a growing tendency toward scientism -- unthinking acceptance of scientific ideas, and a tendency to discount ideas that science can't address."

Science as a peril

Spielberg also regards some aspects of science, including biotechnology, as dangerous. "Every gain in science involves an equal and opposite reaction -- a loss, usually a loss of the environment," he said in an interview. "Science is intrusive. I wouldn't ban molecular biology altogether, because it's useful in finding cures for AIDS, cancer and other diseases. But it's also dangerous, and that's the theme of `Jurassic Park.' "

Eugene Gaffney, the curator of vertebrate paleontology at the American Museum of Natural History in New York, which plans to exhibit some of "Jurassic Park's" model dinosaurs, said he had some misgivings about the film.

" `Jurassic Park' has a Frankenstein aspect, as did a number of Mr. Crichton's books," he said. "I'm not too happy about that. Unfortunately, though, the Frankenstein view of science has become very strong in our society."

Copyright © 2024 Amberica West - All rights reserved.

(719) 258-9319

  • twitter logo
  • facebook logo
  • email logo