Fans of this page may remember that two issues ago, the ScienceLite desk got into trouble for feigning intelligence and evolutionary insight using a quote from Jurassic Park. Sadly our editor was sharp enough to realise the quote’s origin and call us out for it, ensuing much embarrassment. Today however, we have a legitimate reason for bringing the dinosaur blockbuster up again.
Damn that wonderful film for getting our hopes up that one day we too would be able to bring back the dead dinos by extracting 80 million year old DNA from amber-trapped mosquitoes. Now scientists from the universities of Perth and Copenhagen have discovered that a future Jurassic Park scenario looks very unlikely indeed. The researchers have sadly discovered that genetic material cannot be recovered from dinosaurs, putting an end to hopes of ever cloning a Tyrannosaurus Rex.
“This confirms the widely held suspicion that claims of DNA from dinosaurs and ancient insects trapped in amber are incorrect,” said Simon Ho, a computational evolutionary biologist at the University of Sydney, of the study.
We are devastated. ScienceLite never really got over our childhood dinosaur phase and have until now refused to give up hope that cloning of our prehistoric friends could take place. Sadly, it’s less a question of “life will find a way” than “Science can no longer find a way.”
DNA is made of strong stuff; two stands of nucleotides with many intermolecular forces binding and coiling it tightly together in a beautiful double helix. However, it doesn’t last forever and the bonds can be damaged and eventually break. The researchers in this particular study (published in Proceedings of the Royal Society B) found DNA’s rate of decay to be 521 years based on comparisons of DNA from 185 fossilised leg bones from three moa species – a prehistoric bird that once dominated New Zealand’s unique ecosystem before humans were present.
All the bones had been collected from within a five kilometre radius, and buried at an estimated average temperature of 13 degrees Celsius. The similar preservations conditions are key for an experiment like this to ensure a reliable figure for the DNA decay rate could be determined as there are many factors that can affect the rate of decay: soil acidity, bone health, temperature etc.
A decay rate, or a half-life means this: after 521 years, half of the bonds between nucleotides in the backbone of a sample would have broken; after another 521 years half of the remaining bonds would have gone; and so on. This means that even under ideal preservation conditions, all DNA bonds would be completely destroyed in bone after 6.8 million years. So we’ll just have to find something else to fill the dinosaur-shaped hole in our lives. Thanks for ruining everything, laws of physics.
On a more positive note, the rate of DNA decay is actually about 400 times slower than previously thought, so it may be possible for other extinct animals to one day be cloned. We’re quite partial to a woolly mammoth here at ScienceLite. It is speculated that it could soon be possible to implant a mammoth embryo into an elephant’s uterus to result in baby mammoth cuteness. We live in hope.