Around 130 million years ago, a weevil gorged itself on wood pulp and died a sticky death in the relentless grasp of slow-moving resin. That weevil lived alongside the dinosaurs; its death may even have occurred in the presence of brachiosaurus, which once ambled around the same forestland. But what mattered most to researchers who found it in the present day were the short, fragmentary strands of DNA they had managed to extract from the insect. This was, they believed, the oldest DNA ever recovered.
The prestigious science journal Nature published this breathtaking new discovery in June 1993, a single day before another momentous occasion: the release of Jurassic Park. It seemed like the perfect stroke of luck for famed director Steven Spielberg. The publicity came not from his studioâ€™s $65 million promotional plan, but from real, legitimate scientists. (Whether the studyâ€™s release was a coincidence, or Nature timed the article to the movie is unclear, but it certainly seemed intentional to the public and the scientific community.)
â€śThe effect was really important,â€ť says science historian Elizabeth Jones, who is currently at work on a book on the story of Jurassic Park and ancient DNA. â€śIt boosted ancient DNA as an early science. Something that people had never heard of suddenly became extremely popular.â€ť
It was a prime example of how science and science fiction can collide in the real worldâ€”each can boost the other, and one realm can often nudge another in a different direction. While Jurassic Park may not have existed without prior scientific hypotheses, it also pushed that nascent science into the spotlight before it had withstood the necessary scrutiny by the rest of the scientific community.
The original source for the Spielberg thriller was a book by Michael Crichton, also called Jurassic Park. Thanks to Crichtonâ€™s reputation as a popular author, and a visceral story pitting the ingenuity of human scientists against their Frankenstein-like creations, the book had so much hype that studios were jockeying for rights to a film adaptation before it was even published in 1990. But Crichton didnâ€™t pull the idea of out thin air. Heâ€™d been inspired by scientists, who were digging deep into the past in search of clues about life on Earth before the rise of Homo sapiens.
One of his first clues came from a study published in 1982 by entomologist George Poinar, Jr. and colleagues. The researchers examined a fossil fly found in amber thought to be 40 million years old, and suggested that the amber had preserved intracellular structures in what they deemed â€śan extreme form of mummification.â€ť A colleague suggested that it might be possible to extract DNA from the specimenâ€”providing scientists with the DNA of an ancient creature for the first time.
Crichton heard about the study, and within a decade a Hollywood film crew was visiting Poinarâ€™s lab.
â€śMichael Crichton contacted us separately and flew out, and we talked to him. Very nice, tall person. Then, that was it,â€ť Poinar told Science Friday in 2016. â€śThe next thing we knew, the book was out and then the movie was out.â€ť But if Poinarâ€™s work influenced Crichton, the eventual manifestation of the authorâ€™s vision may have also influenced the scientist: Poinar and another researcher, Raul Cano, were the ones who published the 1993 study on the weevil.
But when Jones began her research on the origins of the Jurassic Park story, she came across something surprising. In one edition of Crichtonâ€™s book, the acknowledgement section thanked Poinar. In another edition, thereâ€™s a new name: Charles Pellegrino, a writer who published a story in 1985 called â€śDinosaur Capsuleâ€ť in the speculative fiction magazine Omni. That story also explored the possibility of bringing dinosaurs back to life by mining fossilized DNA.
â€śThereâ€™s a lot of controversy between Poinar and Pellegrino about who has priority to the Jurassic Park idea,â€ť Jones said. â€śIt goes back to the context of genetic engineering at the time, the hope and the hype but also the fear of what we could create.â€ť
Following the release of the movie, scientists like Poinar and Raul Cano were both quick to point out that bringing dinosaurs back to life was impossible. But they were nevertheless swept up in the promise of what ancient DNA could revealâ€”and they were far from the only ones.
In fact, in 1992, both Canoâ€™s team and a group of researchers out of the American Museum for Natural History (AMNH) published papers claiming to have extracted DNA from insectsâ€”an extinct bee and an extinct termite respectivelyâ€”that lived 30 million years ago. Competition between the two groups for flashy breakthroughs was fierce.
When the 1993 study came out, David Grimaldi, a lead researcher for the AMNH team, expressed disapproval at the other teamâ€™s methods. The team had been forced to destroy the weevil, because part of its body was needed for the DNA-generating process, called polymerase chain reaction amplification or PCR. The technique, first developed in 1985, used a solution to make millions of copies of a small segment of DNA so that it could be sequenced and analyzed.
â€śWeâ€™re not interested in destroying specimens simply to break the record for finding the oldest DNA,â€ť Grimaldi told the New York Times. â€śThat weevil was probably unique, and now itâ€™s at least partially destroyed, without a thorough analysis of its morphology that would have helped us to determine its place in evolution.â€ť
But there was another problem with the process, aside from its destructiveness. That was how prone it was to contamination. Basically, if any DNA from the researchers themselves, or organisms in their labsâ€”from bacteria to mold spores to traces of insect DNAâ€”got into the solution, it threw off the results. And that problem was being encountered again and again as other scientists tried to replicate Canoâ€™s astonishing result.
In 1997, a group of researchers conducted a series of experiments in which they tried and failed to obtain ancient DNA from numerous fossils, including bees and termites. Their results â€śbring other claims of amplifications from amber fossil insect specimens into question,â€ť wrote author Kimberley Walden and colleagues at the time. As for Canoâ€™s weevil, its DNA sample â€ścannot be replicated because it was a unique specimen and, in light of our results, is extremely questionable.â€ť
A year later, another research team concluded that the DNA sequence supposedly obtained from the weevil came from fungal contamination. â€śOther amber-entombed and extant insect sequences obtained by this group have been called into question,â€ť the researchers added in the journal Molecular Biology and Evolution. Researchers began backing away from previous claims about DNA extracted from insects in amber, and turning their attention elsewhere. It seemed the world had been too quick to jump at the promise of ancient DNA.
Martin Jones, author of the book Unlocking the Past: How Archaeologists are Rewriting Human History with Ancient DNA, summarized the sentiment thusly: â€śThe excitement about new results had infected everyone, including the referees used by high-profile scientific journals â€¦ There was a palpable sense that the convoy of ancient DNA hunters should adopt a more cautious respect for the highway.â€ť
Today, fossil findings in amber are still going strong. Last week, paleontologists at the Field Museum published a study on a new species of featherwing beetle that lived 99 million years ago, and was found encased in the golden depths of hardened resin. Christened Kekveus jason, the bug is barely the size of a period at the end of a sentence and shares morphological similarities with beetles alive today.
Notably, the scientists made no effort to extract DNA from the beetle. In fact, to this day, weâ€™ve never extracted dino DNA. Part of the reason for that change in the field at large is because in 2012 researchers calculated DNA has a half-life of 521 years. That means all the DNA would be destroyed within 6.8 million years, if not much earlier. â€śIt is impossible to extract DNA from specimens in amber even with the latest technologies,â€ť said Shuhei Yamamoto, one of the authors of the new paper, by email. â€śMost people just describe the species like I do.â€ť
But Jones doesnâ€™t necessarily see the hype surrounding ancient DNA via Jurassic Park as a story of failure. â€śA lot of science is trial and error and finding out what we donâ€™t know,â€ť Jones says. â€śWhat makes ancient DNA and the story of Jurassic Park so interesting is that figuring out what ancient DNA could or couldnâ€™t do wasnâ€™t a private affair. Researchers were responding not just at their conferences and their peer review articles, but on a public platform.â€ť
In other words, while the science might not have been right the first time around, it was still part of the exploration process. And for once, the public got a taste of what that debate looked like even as scientists were working out the finer details. So maybe ancient DNA canâ€™t bring back the dinosaurs. But it still brings the tantalizing promise of resurrecting more recent animalsâ€”like, for instance, woolly mammoths.