Dreaming of Jurassic Park? DNA says thanks, but no thanks
Sorry to burst your bubble, but Jurassic Park will have to remain a daydream -- thanks to a new DNA study.
Who doesn't remember the film Jurassic Park? Raptors and a Triceratops, rebellious DNA fueled by mutated frog codes, the branded lunchboxes and enraptured paleontologists. It was meant to teach us that messing with nature could bring back the monsters of the past -- but we could all still dream.
Now, however, a study has revealed just how long dinosaur DNA lasts -- and its longer than we thought, but not long enough.
521 years is the half-life of a DNA strand, according to work published in Proceedings of the Royal Society. A team of palaeogeneticists led by Morten Allentoft at the University of Copenhagen and Michael Bunce at Murdoch University in Perth, Australia, conducted the study.
Examining 158 leg bones that belong to three species of an extinct giant bird called a moa, each DNA-containing fossil was between 600 and 8,000 years old. The samples, found in New Zealand, were used to calculate degrees of DNA degradation -- and therefore what could be recovered feasibly.
By comparing the specimens' ages and degrees of degradation, the scientists calculated DNA's half-life. After 521 years, half of the bonds that bind nucleotides together break, and in another 521 they would break again, and so on.
What does this mean? No Jurassic Park for you. Even if a bone was preserved at the ideal level of −5 ºC, almost every bond would break before the end of 6.8 million years. But after approximately 1.5 million years, the DNA would be unreadable. Not much luck for 65 million year-old bones then.
"This confirms the widely held suspicion that claims of DNA from dinosaurs and ancient insects trapped in amber are incorrect," says Simon Ho, an evolutionary biologist at the University of Sydney in Australia. "However, although 6.8 million years is nowhere near the age of a dinosaur bone -- which would be at least 65 million years old -- We might be able to break the record for the oldest authentic DNA sequence, which currently stands at about half a million years."
Whether these results would be the same in environments including frost and caves remains to be seen. Inerestingly, age differences only accounted for 38.6 percent of variation in moa-bone DNA, which suggests that other factors come into play -- including soil chemistry, excavation techniques and potentially even the time of year the animal died.