The Science of Jurassic Park
and The Lost World
Or, How To Build A Dinosaur
[review] [excerpt] [endlinks] [purchase]

by Rob DeSalle and David Lindley
Basic Books, 1997

Reviewed by Keena D. Lykins

Recipe for Resurrecting a T-Rex

• 1 amber nugget. Must be at least 65 million years old.
• 1 preserved mosquito. Must have swallowed blood from a dinosaur within minutes of being encased in the tree sap that became the nugget.
• 1 kit.
• Several thousand DNA sequencing machines.
• Lab technicians as needed.
• More money than Bill Gates.

Using a lab cleansed of all foreign DNA, pry open the amber, taking care to mangle the insect as little as possible. Once you've freed the mosquito from its yellow coffin, extract its stomach contents using a DNA-free needle. Avoid the insect's own DNA. Using your kit, multiply the fragments of DNA millions or billions of times. . . .

With tongues firmly planted in cheeks and with minds completely focused on facts, Rob DeSalle and David Lindley dissect the science in the popular books and movies Jurassic Park and The Lost World to tell their audience that dinosaur reconstruction is an expensive, probably impossible proposition.

And while other scientists and science writers effectively dismissed the proposal with a one-sentence rebuttal - "It can't be done now, and it probably will never be done" - DeSalle and Lindley use the enormous popularity of the books and films as an opportunity to pass on more than a little science fact to the dinosaur-crazy general public, which is not limited to children. The authors take their readers through the real and theoretical steps needed to reverse the extinction process and reintroduce the "terrible lizards" to planet Earth.

They are exceptionally qualified to lead this expedition. DeSalle is associate curator at the American Museum of Natural History in New York City. In 1992 he isolated what was then the oldest known fragment of DNA. Lindley, a former editor at both Science and Nature, is now an editor at Science News. He has written two books, The End of Physics and Where Does the Weirdness Go. Together, the two take an entertaining scientific tour of a science fiction fantasy.

From the cave "Mano de Dios," where the authors begin correcting the screenwriters - amber is found not in jungle caves but on hilly scrubland - to the 22-square-mile island that is, frankly, much too small to support a diverse population of dinosaurs, readers traverse the globe and the realms of Hollywood. We learn that when it comes to DNA and resurrecting dinosaurs, Jurassic Park and Lost World author Michael Crichton oversimplifies the science, and at some points in the narrative completely glosses over the facts, never letting them get in the way of a good story. That is Crichton's job, of course, and he is phenomenally successful at it. That success makes it important for qualified scientists and science writers like DeSalle and Lindley to add, for the public record, a little reality to the imagination.

Although readers never know which author contributes what to the book, the writing is playful and straightforward without dumbing down the subject matter for nonscientists. Readers are taken through the layers of science fiction and science fact, learning where they intersect and where they diverge. In the hands of a skillful writer such as Crichton, the line between the two can be so blurred as to be invisible. With equal skill, Lindley and DeSalle redraw the line.

Consider their position "No, dinosaurs can not now and probably never will be resurrected from collected DNA found in the stomach of a mosquito entombed in ancient amber." Why, exactly? First, Crichton's most obvious assumption is essentially and obviously correct. Since dinosaurs were made from the same stuff - proteins, sugars, water, minerals, etc. - that we are, the trick to recreating them is not in figuring out the ingredients but in learning how to mix them. DNA is the prime ingredient in any recipe for recreating any life form. So, if dinosaurs are going to be reborn, it is through reconstituting preserved DNA.

The crucial word is preserved. DNA is not a Herculean molecule. It breaks down quickly once outside the cell. So unless it is somehow embalmed, we are not going to find usable DNA. Amber, fortunately, is very good at preserving the hapless creatures occasionally trapped in it, so perhaps their DNA is preserved along with them. But Steven Spielberg's and Michael Crichton's "scientists" (and we) are not going to find an amber-preserved dinosaur, not even a compy (the little scavenger that runs around in The Lost World).

Enter the insect. Dinosaurs are believed to have had thick, scaly skin like modern alligators. So mosquitoes would have had a harder time drawing blood from them than from our mammalian predecessors. But if a mosquito were smart or lucky enough to head for the eyes, where the skin is usually thinner, it might have a dined on a dino. Then, flying to a nearby Hymenaea tree, the bloodsucker would have rested on the bark and begun digesting its meal as it was suddenly encased in a thick glob of tree sap.

Sealed from oxygen and bacteria that would normally decompose and recycle it, the mosquito is embalmed and on its way to becoming a collector's item. Over millions of years, the goop encasing it solidifies and becomes amber. We find it, break apart the amber, and extract a fragment of the insect's last supper. One problem: The mosquito was eating that DNA, so it may have been digested before it gave up its six-legged ghost.

Another and better chance of finding dinosaur DNA trapped in amber, according to DeSalle and Lindley, is not through insects but through skin or flesh captured in the golden stone. Amber containing dinosaur skin or scraps of flesh left behind by a messy eater is much more likely to yield what a cinema scientist needs. But that phenomenon is rare, so our mad scientist/entrepreneur would have to find and buy many thousands of pieces of appropriate amber. Incidently, the best place to find amber of the appropriate age, according to DeSalle, is not the Dominican Republic (as portrayed in the movie version of Jurassic Park) but in a place much more mundane: New Jersey.

Once we find the requisite meat-filled amber, the second problem would be extracting it to see if DNA has been preserved. This is a much more complicated step. Of course, the usual precautions to prevent contaminating the DNA sample will have to be stringently applied here, since polymerase chain reaction takes any DNA present and amplifies it. As recently reported by Nature, humans leave bits of DNA on nearly everything they touch: clothes, doorknobs, even fingerprints left on drinking glasses and pens. So scientists have to take extra precautions to avoid accidentally harvesting, resurrecting and "hatching" the UPS driver who delivered the amber.

Once the environment is cleansed of all foreign DNA, our "dinosaur" blueprint is carefully extracted, isolated, spun, multiplied, sequenced, coiled, incubated and, if fate is kind, hatched. Until that moment, our mad scientist will not know if he's recreated a Jurassic rat or a velociraptor.

As the writers point out, this sounds simpler than it is. First, the dinosaur DNA, if that is what we find, is going to be extremely fragmented. The average human genome is 3 billion bases long; presumably the run-of-the-jungle T. rex had a DNA strand at least that long, if not longer. And because of DNA's fragility, the fragments would be extremely short. The writers estimate that dinosaur genome would be broken into segments about 500 bases long, or 100 million fragments of DNA. DeSalle estimated that our mad, ambitious dinocloner would need an automated storage facility about the size of a football stadium, hundreds if not thousands of technicians to work with the DNA and, eventually, 200 sequencing machines working nonstop for three years to resequence the dinosaur DNA.

So even if our scientists manage to form the complementary DNA strands and patch the gaps in the fragments using base sequences from birds, the closest living relatives to dinosaurs (Crichton uses amphibian DNA in his book, which creates another problem), this work will take years. And once the lab is done mixing ingredients, scientists would still have to figure out how to go from a DNA strand to a living, breathing dinosaur.

None of this is going to be inexpensive. A simple kit costs a couple of thousand dollars. For $12,000, you can get a machine with robotic arms that pick up the test tubes and alternately place them in hot and cold water. DNA multiplies best when the temperatures are changed as quickly as possible, so a top-of-the-line machine is probably most useful. And when it comes to filling in the gaps of the dinosaur genome, hundreds of technicians will be needed. First, they will have to decipher the genome of whatever creature is thought to have the perfect "filler" DNA. Then the fragments have to be put together again in the proper order. A sequencing machine costs about $125,000, and our writers estimate at least 2,000 such machines will be needed - totaling $230 million - if the work is to be completed in our lifetime.

And once the DNA double helix has been completed, someone has to figure out how to package the code into chromosomes, fertilize it, put it into or create an egg for it (using techniques developed for cloning), and then raise the little monster.

There's more, and as the reader continues on this educational journey, she learns that Jurassic Park and The Lost World make for fun science fiction, but that their science fact falls short enough to justify this entertaining, educational book.

Keena D. Lykins is an award-winning writer and editor.

Excerpt

You'll have realized by now that making dinosaurs from ancient scraps of preserved DNA is no easy matter. . . . And even if sufficient dinosaur DNA is found, there are countless difficulties and complications in creating a dinosaur - enough to make the task essentially impossible. But the sorts of problems that remain perplexing - how to identify and "mend" unknown genes, how to persuade an egg cell to take up a foreign genome, how to manipulate the genetic characteristics of a growing embryo - are those that scientists are working on right now, in many different contexts, in laboratories around the world."

Tell us about your favorite books.

Endlinks