Amber With Inclusions

About 700,000 centuries later, a scientist drills into the amber tomb and extracts T-Rex DNA from the dinosaur blood cells within the perfectly preserved body of the mosquito. From the DNA blueprint, a T-Rex is cloned. This is essentially the underlying theme behind the story of Jurassic Park.

In 1992 two independent research teams published their remarkable discoveries about ancient genes (DNA) preserved in amber, and the exciting new field of molecular paleontology officially emerged. George Poinar, a University of California entomologist extracted DNA from a 30 million-year- old stingless, tropical bee preserved in Dominican Republic Amber (Medical Science Research Vol. 20, 1992). In fact, Poinar's earlier research on ancient insect DNA (Science 215, 1982) provided the inspiration (at least in part) for Michael Crichton's book Jurassic Park, followed by the Steven Spielberg blockbuster movie, one of the most popular box office hits of all time. As Poinar's team at Berkeley conducted their research, another team led by David Grimaldi and Rob DeSalle at the American Museum of Natural History extracted DNA from a 30 million-year-old termite entombed in Dominican Republic amber (Science Vol. 257, 1992).

During the summer of 1993, several additional articles about the extraction of DNA from amber appeared in Volume 363 of the prestigious British journal Nature. In an article by Raul Cano of California Polytechnic University, San Luis Obispo, DNA was extracted from a 120-135 million-year-old weevil found in Lebanese amber. This discovery of insect DNA is well within the time frame when enormous dinosaurs roamed the earth. In another article by Cano and Poinar, chloroplast DNA dated at 35-40 million years old was extracted from the leaf of a West Indian locust preserved in Dominican Republic amber. The leaf is from the extinct species Hymenaea protera, the probable ancestor of present-day African and New World copal-producing Hymenaea species.

These remarkable new DNA discoveries in amber may provide the answers to such profound questions as why have insects changed so little during the past 150 million years, while other animals have evolved dramatically. Using sophisticated computer analysis, the precise DNA sequencing of ancient genes can be used to construct phylogenetic trees showing the origin and taxonomic relationship of animals. This information can be correlated with evidence from plate tectonics to show the ancestral migrations of animals and plants as they literally rode on the moving continents. DNA from ancient plants opens up a Pandora's Box of fascinating research, and may shed some light on the rather sudden and mysterious origin of flowering plant species.

In case you are worried about the reality of Jurassic Park, it is very unlikely that a five ton T-Rex or vicious Velociraptor will ever be cloned from DNA preserved in amber. Even if a DNA sample from the stomach of a blood-sucking insect could be identified as the insect's last supper on the skin of a T-Rex, the odds against ever reconstructing a T-Rex are overwhelming. Reassembling the complete DNA genome of a dinosaur from gene fragments trapped in amber would be like trying to reconstruct the complete Encyclopedia Britannica from a cupful of letters in alphabet soup.

However, it may be possible to clone ancient viruses and bacteria preserved in amber. Since they have fewer genes, reconstructing the DNA of a virus or single-celled bacterium is within the realm of today's modern biotechnology. Bringing extinct microorganisms back to life after many millions of years could have some valuable medical implications, such as the origin of present- day disease organisms. There could also be some frightening consequences equal to those of Jurassic Park, such as bringing back to life a serious pathogen--perhaps an AIDS virus that killed off the dinosaurs. The latter scenario is reminiscent of another Michael Crichton book, The Andromeda Strain.

So the next time you gaze into your favorite piece of amber jewelry, think about the DNA of microbes that it might contain, quietly resting in a harmless abiotic state for the past 40 million years.