Title: Resurrecting dinosaurs.
Subject(s): DINOSAURS -- Genetic engineering
Source: Omni, Fall95, Vol. 17 Issue 8, p68, 6p, 3c
Author(s): Pellegrino, Charles
Abstract: Focuses on the possible resurrection of dinosaurs through
cloning. Demonstration of dinosaur cloning in the movie `Jurassic
Park'; Advances in paleogenetics that make it possible to clone
dinosaurs; Sources of dinosaur DNA.
AN: 9608050070
ISSN: 0149-8711
Note: Tucson-Pima Public Library subscribes to this magazine.
Database: MasterFILE Elite

RESURRECTING DINOSAURS

Jurassic Park could be open for business in 20 years. So says the man
who first proposed cloning dinosaurs from ancient insects in amber.

There was a time, about 15 years ago, when I needed at least a
half-hour of back-and-forth questions and answers just to convey the
barest essentials of how it might be possible to derive from a fly in
amber a living, breathing dinosaur hatchling. And yet, as I write, I
have just heard Jay Leno ask, "How in the world did we get all these
dinosaurs in Congress?"

"I get it," he says, after a pause. "Some scientist found a piece of
amber with a mosquito in it . . ." and the audience bursts into
immediate laughter.

They got it, every one of them. Thanks to Michael Crichton and Steven
Spielberg, every eight-year-old child with a love of dinosaurs (which
is to say, every eight-year-old child) now knows the dinosaur-cloning
recipe inside and out.

I would never have believed this possible, back when lengthy
explanations left colleagues at Victoria University, Berkeley, and the
Smithsonian exhausted and confused by what was to even the most
open-minded of them "a totally bizarre thought," if not "downright
crazy" Perhaps my explanations were part of the problem: brevity was
never one of my virtues. Indeed, after watching me go on about amber
carbonaceous meteorites, and resurrecting the dinosaurs (sometimes in
the same sentence), science-fiction writer and then-Omni editor Ben
Bova agreed with one of my Jesuit teachers that "going to Charlie and
asking a question can be like going to a fire hydrant for a sip of
water."

And so it turned out that, by 1981, I had managed to utterly confound
a great many of my colleagues. About that time, a Berkeley team had
begun to send me electron micrographs showing strands of what appeared
to be ancient mitochondrial DNA preserved in an amberized insect
(hints of a dinosaur starter kit, if you will). But members of that
same Berkeley team originally held such jaundiced opinions of the
feasibility of dinosaur cloning that, for more than two years, they
blocked the recipe's publication in Smithsonion. They had themselves
produced micrographs of what may yet prove to be one of the biological
discoveries of the century--evidence that whole libraries of ancient
DNA may lie dormant within the earth--but they refused to see it.

In frustration, I eventually brought my paper to more forward-looking
people at Omni, who published it in the January 1985 issue. Unlike a
lot of my other works, the "Dinosaur Capsule" article seemed to
produce almost no response at all. I guess 'it was just the sort of
thing you didn't discuss in polite scientific circles in those days.
Looking back, I wonder if anyone except Michael Crichton ever read it.
But does it matter? He was enough.

With Crichton's novel, Jurassic Park, and Spielberg's subsequent
phenomenally successful film adaptation, science fiction once again
made complex scientific ideas respectable. What Jules Verne did for
submarines, what Robert Heinlein and Arthur C. Clarke did for
translunar flight, Crichton and Spielberg did for the emerging science
of paleogenetics. All that remains now is for the realities of
scientific achievement to once again catch up with the fiction.

In my article of 10 years ago, I predicted that the technology
necessary to make the cloning of dinosaurs at least thinkable was
about 30 years away. Looking at the advances in genetic and computer
technology that have taken place since, I'd say we are right on
schedule, with 20 years still to go.

Perhaps the most important genetic advance we've seen so far, in terms
of paleontology, is a little tongue-twister called the polymerase
chain reaction (PCR). It works somewhat like a DNA photocopier, making
it possible to amplify, millions of times, a faint signal consisting
of only a few fragments of DNA. Using PCR, a team of paleontologists
at the American Museum of Natural History in New York City became the
first to identify replicable pieces of DNA in an amber-embedded
termite from the Dominican Republic dating back to 25 to 30 million
B.C. If portions of a genetic coding system can survive that long,
it's not much of a leap from 25 or 30 million years ago to, say, 70 or
90 million years ago--the time of dinosaurs.

Following the termite discovery, paleontologist Gerard Case--who took
me to the New Jersey amber beds in 1978 and whose discovery of
95-million-year-old biting flies at about the same time I began
finding intact muscle fibers in amberized bees actually triggered the
Jurassic Park recipe--led entomologist David Grimaldi, whose team had
identified the termite DNA, to a new amber deposit in New Jersey. The
discovery greatly expanded the world's supply of Cretaceous-period
biting pests, which had both motive and opportunity for biting
dinosaurs. During the summer of 1993, Case and Grimaldi mined out a
Cretaceous vein that produced 60 pounds of amber containing scores of
biting flies and other insects.

Excavated from a tomb 24,000 times older than any pharaoh's, the
little handful of flesh-feeding creatures is as priceless as the
golden death mask of Tutankhamen. We would all love to get into any
saurian cells clinging to their mandibles, but paleontologists are by
nature a rather patient lot, so the organic gemstones must ideally
remain under refrigeration (to stop the amber itself from evaporating
its oils and cracking now that it has been exposed to air), waiting
for technology to catch up with the dream. PCR may be advanced
technology by today's standards, but compared to the microsurgical
techniques that we will need to ferret out dinosaur DNA, it is like
trying to figure out how an antique watch worked by smashing it open
with a sledgehammer.

If we are lucky enough to find a mite or a horsefly that blundered
into a pool of sun-warmed or very fluid tree sap after biting a
dinosaur, then the resin might have preserved in that insect thousands
of dinosaur cells, each containing in its nucleus a copy of the
genetic blueprints necessary for building a dinosaur. My colleagues
and I are drawing up plans for microscanners that--when we have the
technology to build them, in about 15 years--will allow us to probe
those ancient cells and build copies of their genetic blueprints in a
computer. The trick lies in removing the nucleus of an individual cell
in about 10 pieces, without disturbing any of its neighboring--and
equally precious--cells, and then preserving the pieces so that we can
scan them as often as we like, as easily as one scans a laser-engraved
compact disk. In this manner, we can build complete copies of dinosaur
chromosomes by sampling as few as a dozen amberized cells--and, as I
have said, a single bite from a fly probably contains thousands of
cells.

Considering the value--both scientific and monetary--of each of those
cells, we cannot afford to sacrifice more than a dozen cells to come
up with dinosaur genetic blueprints. Translation: Searching for
dinosaur genes with present-day technology is out of the question. PCR
would require cracking open a piece of amberized flesh and using up
every one of the thousands of cells within. The process is somewhat
like burning a book as you read it, capturing only a sentence here and
there. None of my colleagues want to vandalize ancient treasures
simply to enter the record books as the first to recover dinosaur
genes from amber. The saurian tissue, if such is preserved, has
already waited 95 million years. Surely we sapient newcomers can wait
15 or 20 years more.

On another front, there may exist on the horizon a newer and much more
expendable source of dinosaur DNA. During the summer of 1993, a
remarkably well-preserved Allosaurus femur of Jurassic age was smashed
in half during shipping to fossil hunter Mark Newman, who noticed
something he'd never seen before spilling out of its center: a
reddish-brown substance that looked for all the world like intact bone
marrow.

I know someone who may be interested in this, Newman thought, and a
week later, physicist Jim Powell and I were looking through an
electron microscope at the impossible. The bone must have baked under
the sun for hundreds, perhaps thousands, of years before water got
anywhere near it, until it somehow mummified. We beheld a strange
landscape of marrow vesicles studded with objects that looked like
blood cells with a histology suggestive of . . . ostrich!

We had heard rumors of a similar discovery at John Horner's lab at the
Museum of the Rockies. I made a call to Horner--the paleontologist
upon whom Sam Neill's character in the film version of Jurassic Park
was based--and he immediately referred me to Mary Schweitzer, who had
found equally strange structures in a T. rex bone. A quick comparison
showed that our Jurassic material looked chillingly like what she was
pulling out of the Cretaceous Period.

Schweitzer speculates that many ancient bones contain some of their
original organic material intact. Ever since she brought up this
possibility, I've been unable to force out of my mind some
15-million-year-old crabs I found with what appeared to be original
pigment in their claws, displaying the same distinctive pattern I had
found on the claws of their present-living relatives. I remember
making excuses for the fossil record, suggesting that organic pigments
had somehow affected the process of mineralization, so that darker
minerals settled into the same black spots seen on' the claws of the
crabs' descendants, thus producing the illusion that a petrified crab
could still display its original colors after millions of years. But
now such oddities begin to make perfect sense. Having looked at what
the rest of us have seen for decades and thought what none of us had
dared think, Schweitzer is turning much of what we thought we knew
about the process of fossilization upside down.

Every new class of paleontology students learns from textbooks that
fossils are more or less mere 3-D images of once-living matter, with
none of the living matter still existing. American Museum of Natural
History entomologist Paul Wygodzinski and I discovered in 1978 that
preserved muscle fibers in amberized insects presented an astonishing
exception to this rule, but with the Schweitzer revelations the
importance of my amber studies diminishes. This is no cause for
despair, only applause. When a pet theory is altered or diminished
under the weight of new evidence, the new theory that rises on its
foundations (or sometimes on its grave) may be even more exciting. The
sort of preservation hinted at in amber, offering the best known
protection against the ravages of time, might actually be more the
rule than the exception. Thus, the "exception" that Wygodzinski and I
found may well be no exception at all but evidence of a new rule.

And the evidence mounts. We already have in hand amino acids,
porphyrin molecules, and other ring-shaped organic compounds that have
survived more than four billion years of cosmic-ray exposure inside
certain carbon-rich, stony meteorites. As above, so below. Organic
compounds can be startlingly resilient. Allosaur marrow is only a few
tens of millions of years old, and it may be time to begin looking for
dinsaur DNA in places we never imagined it to exist.

Allosaurus: best described as a leaner, meaner version of T. rex. Just
imagine a velociraptor 18 feet tall. When Powell and I first began
probing the allosaur marrow, we considered our initial observation too
crazy: Certain structures in the marrow looked a little too much like
they belonged to birds.

I used to believe that paleontologist Robert Bakker had gotten a bit
too carried away with birds. A Bakker lecture typically goes something
like this: "Bird . . . dinosaur . . . dinosaur . . . bird!" At this
writing, the first attempt to extract DNA from T. rex bones has been
unsuccessful, but certainly there will be further attempts using
better tools. In the meantime, there are tantalizing hints, in the
impossibly preserved fine structures of the bones themselves, that
Bakker has been on the right track all along: Some of the large,
predatory dinosaurs resembled birds more than I thought possible.
After all is said and done, tyrannosaurs and allosaurs begin to look
like parakeets designed by Stephen King.

Ultimately, our breaking of the saurian genetic code will make use of
several simplifications that I have made in the dinosaur cloning
recipe, including a "match and patch" approach that will eventually
allow us to line up copies of DNA segments from as few as 10 cells on
a computer screen, somewhat like markers on a spectrum. All of these
segments will no doubt have been damaged by the decay of carbon 14,
potassium 40, and the occasional cosmic ray, but this problem is not
much different from the one encountered by archaeologists now dealing
with multiple copies of the Book of Isaiah, every one of them
scattered in pieces and mostly missing, among the Dead Sea Scrolls. In
both cases, a program for "matching and patching" missing
segments--for building a single composite "text" from partly damaged
copies--solves the problem. For dinosaurs, "match and patch" means we
won't have to make a "best guess"--as I had proposed in the original
recipe and as bioengineers did in Jurassic Park--requiring us to
borrow missing bits of genetic code from frogs, reptiles, and/or
birds.

Match-and-patch technology will work best with DNA embedded in amber,
where we have already found insect cells so perfectly intact as to
rival the level of preservation achieved when Canadian Balsam, also a
form of tree sap, is smeared over cells during the preparation of a
microscope slide. if a cosmic ray disintegrates a small portion of
DNA, the adjacent sections will be held in place by the surrounding
resin, as if in glue. Still, with an estimated 100,000 genes needed to
build a dinosaur, each cell nucleus can be compared to a partly intact
jigsaw puzzle the size of a small parking lot. For my allosaur femur
and Schweitzer's T. rex bone, in which DNA fragments (if such exist)
were free to migrate, we have much more material to work with--but it
exists as a hodgepodge of multiple copies of the jigsaw puzzle thrown
up in the air and mixed together. Though not impossible to solve, the
bone puzzle will require at least 20,000 times more effort to assemble
than one found in amber.

There may exist, however, a third path to the dinosaur genome, one
that in terms of difficulty and availability of material lies
somewhere between amber and bones. Using high-resolution machines that
were still at an experimental stage, Powell and I made the first
magnetic resonance imaging (MRI) scans of T. rex eggs in 1993. We did
not find embryonic bones inside those eggs, but we did behold a
pale-ontological tale in which a 20-inch-long egg looked as if it was
stepped on shortly after being laid.

MRI enables us to see into dinosaur eggs without having to etch their
mineral casings away with acids, which are notoriously unfriendly to
DNA. Linking MRI scanners to computers, we hope to reconstruct
skeletal dinosaur embryos as on-screen 3-D images. Although some of
the bones nestled within dinosaur eggs are literally paper-thin, the
level of preservation is many orders of magnitude above our
child-size, more easily preserved allosaur femur. If Powell and I are
right, then DNA residing in embryonic bones will tend to be far more
intact than anything we are likely to find in the adult femur.

Now that amber and soon perhaps fragments of bone may yield up
dinosaur DNA, we paleontologists are emerging into a strange new world
in which assumptions about air, water, and sunlight breaking down and
eliminating all old DNA are wrong. I used to believe, not very long
ago; that diamonds were the world's most resilient and valuable form
of carbon. Now I see diamonds about to be dethroned by DNA--by little
snippets of ancient genetic code, passed across oceans of time like
bits of gossip over a backyard fence.

You cannot look at the surreal developments of the past decade and a
half without beginning to wonder what nature has really been up to all
these hundreds of millions of years. Even without assistance from tree
sap-turned-to-amber, DNA is the ultimate survivor, and perhaps even
the ultimate parasite. For billions of years, it has managed to
preserve its same, essential structure, residing for a little while in
you, or me, or a dinosaur, or a bacterium, and then moving on, fully
intact, to the next generation. You may like to think that your genes
serve your best interests, but in a very real sense, it is quite the
other way around. They simply orchestrate the construction of our
bodies, then occupy us for a few decades, with no purpose other
producing or maintaining reproductive systems, so they can carry on in
fresh young bodies just as ours begin to wear out. Every breath you
take, every sip of water, every bite of food immortalizes your genetic
code, not you.

Commenting on this, the philosopher-science fiction writer George
Zebrowski observed, "We, then, are just one of the many masks that DNA
will wear."

So, too, were the dinosaurs. We are learning now that occupying or
renting our bodies is not the only way that DNA survives. So long as
the carriers of chromosomes managed to cover the earth thickly enough,
infecting every nook and cranny with bits of living tissue, some small
amount of DNA was bound to take up permanent residence wherever it
found an environment capable of preserving it. At least in an
analogous sense, the giants do indeed appear merely to have been
sleeping in the earth, waiting for the planet to evolve brains capable
of resurrecting their genetic blueprints. If this is so, do we then
define life as simply a property of the carbon atom, as an
information-storage system written on nucleic acid and read by
protein? And if the answer is yes, should strands of DNA embedded in
amber or bone still be considered alive after tens of millions of
years?

Can it be that we are on the verge of redefining not only the word
"extinct" but our notions of life and death as well? If so, and if we
begin to view DNA as something that merely borrows our bodies for a
while only to move on with contemptuous indifference, then in the end
it is DNA that rules humanity and the earth. Everything else is
hubris.

Which brings us to the notion that, for better or for worse, we will
soon have the ability to take charge not only of our own evolutionary
destiny but that of the entire planet.

Yet--and perhaps reassuringly--technological hurdles remain. Presently
we can print copies of the genetic code, but we can actually read and
understand just a few fragments of the book of life. We are in a
position much like that of the Egyptologists who came upon hauntingly
beautiful hieroglyphs but couldn't read them until the discovery of
the Rosetta Stone. With an effort to catalog and translate the entire
human genome already in the works, science has just begun to carve the
genetic Rosetta Stone. It may turn out that I'm a little optimistic in
believing that dinosaur cloning lies only 20 years away. It could be
50 years, but I agree with Spielberg that we are looking at science
eventuality, not science fiction.

So while I wait here at the midpoint of the last decade of the second
millennium, with both amber and dinosaur marrow under refrigeration, I
rejoice to see how closely science and science fiction have
dovetailed. But it is also impossible for me to forget the warning
spoken by Jeff Goldblum's character in the film: "Your scientists were
so preoccupied with whether or not they could that they didn't stop to
think if they should." A few people have suggested that I should be
offended by such statements, that the film is "antitechnology," and
that it "trashes" my ideas. Not at all. Jurassic Park does what good
science fiction is supposed to do: It looks ahead to what bridges we
may soon be building and asks us to consider very carefully what
trolls may be hiding under those bridges. Crichton and Spielberg
challenge us to start thinking about the trolls before we arrive at
the bridge, before we have to deal with them.

I don't really believe that the formerly extinct will ever get loose,.
eat our lawyers, and threaten to take over the world. But I do see
more subtle dangers on the road ahead. Consider recent proposals to
sample all the plants and insects of the Amazon and to preserve their
tissues in liquid nitrogen. Already, because of my recipe, it is
becoming increasingly fashionable in certain industrial circles to
stop worrying about felling the forests, because with care the extinct
can be brought back again. So here we sit, you and I, on the brink of
a genetic frontier in which our hopes of resurrecting extinct life
forms may actually encourage the very behaviors that cause extinction.

A fanciful hope--that is how it began, as a hope to invent the
ultimate paleontological tool that would allow me to study my favorite
creatures face to face. But what did the Greeks name the last demon to
escape Pandora's box; the one Pandora almost managed to slam the lid
on; the most horrible of them all, because it came disguised as a
blessing? Did they not call it Hope?

ILLUSTRATIONS

~~~~~~~~

ARTICLE BY CHARLES PELLEGRINO
_________________

Copyright of Omni is the property of General Media, Inc. and its
content may not be copied or emailed to multiple sites or posted to a
listserv without the copyright holder's express written permission.
However, users may print, download, or email articles for individual
use.
Source: Omni, Fall95, Vol. 17 Issue 8, p68, 6p, 3c.
Item Number: 9608050070