The Amber Forest: A Reconstruction of a Vanished World
by George Poinar Jr., by Roberta Poinar. with photographs and drawings by the authors.
Princeton University Press, 239 pp., $29.95
A tree once grew on the Caribbean island of Hispaniola that had the strange ability of freezing moments in time. A member of the honey locust family known as the algarrobo, it vanished millions of years ago. Fortunately for us it left behind tiny time capsules—fragments of amber in which we can read the story of a marvelous lost world. Entombed in some fragments are the remains of plants and various animals, the most common being the bodies of insects. For sheer beauty, mystery, and the capacity to astonish, these fossils are difficult to surpass.
The algarrobo tree produced a copious, clear, sticky resin. Whenever the tree bled from borer hole or fracture it extruded the substance in quantity. Sometimes the peculiar sap must have run down the trunk like honey, encasing whatever it encountered. At other times it sat atop the wound in a glistening pool, its reflection beckoning enticingly in the dark of the forest. Then a wasp, sweat bee, or beetle attracted to the substance might tumble in. Within seconds it would be engulfed. Life was extinguished almost instantaneously, but the corpse was rendered eternal.
It has long been known that resin has preservative and antibiotic properties, for it has been used in food preservatives, in medicines, and in winemaking since ancient times. Despite great recent advances in chemistry we still do not understand exactly how amber does its magic trick of preserving things so wonderfully. This is because amber is a cocktail of chemicals, including alcohols, sugars, esters, and terpenes whose complexity defies ready analysis. Somehow the brew withdraws water from whatever it engulfs, then fixes the dehydrated tissues and excludes bacteria. To top it all off it hardens when fossilized to a brilliant, transparent, gemlike material.
Although scientists have long appreciated the amber fossils for their ability to reveal something of a vanished world, their true potential as a key to unlocking the past has been recognized only recently. The senior author of The Amber Forest, George Poinar, was the first person to extract DNA from an amber fossil—that of a stingless bee from the Dominican Republic. It is now known that amber is the only substance that can preserve DNA in any form for more than a few tens of thousands of years.
The discovery of amber’s unique ability to preserve DNA over the long term has spawned a whole new industry, which began in 1990 when Michael Crichton published his book Jurassic Park. The story was to become famous and it went on to inspire one of the most popular recent movies. At the heart of the plot lay a plan to extract the DNA of dinosaurs from blood-sucking insects preserved in amber. The fictional researchers then reconstructed the beasts, with well-known consequences.
The authors of The Amber Forest inform us that Jurassic Park is still in the realms of fantasy, for even the DNA from animals preserved in amber is badly degraded, fragmented, and strongly cross-linked with other molecules …