October 11, 2012
DNA Discrepancy: Bad News For Jurassic Genetics
Michael Harper for redOrbit.com — Your Universe Online
Led by Morten Allentoft at the University of Copenhagen and Michael Bunce at Murdoch University in Perth, Australia, a group of palaeogeneticists studied many bones from a Moa bird fossil to understand just how feasible it is to clone a Raptor these days.
"We've been permanently plagued by this Jurassic Park myth that's been kicking around since the early nineties," Bunce told the Sydney Morning Herald, reports the Telegraph. “The myth is still out there. Even other scientists ask whether it is possible.''
Each of the 158 Moa bones were gathered relatively close to one another in New Zealand, (about 3 miles or so apart) were preserved in near identical environments, and are estimated by the team to be anywhere between 600 and 8,000 years old.
After drilling into the core of these bones and examining them, the researchers estimated that DNA actually has a half-life of about 521 years. This means that after an estimated span of 521 years, half of the nucleotides in the sample´s backbone break. In another 521 years, half of the remaining nucleotides also break, and so on.
Even though half of the nucleotides are destroyed after just 521 years, the research team suggests that, under the best conditions, every strand in that DNA would be destroyed after, at most, 6.8 million years. Further crushing Crichton fans, these researchers also suggest that while this DNA could technically exist for upwards of 6 million years, it becomes mostly useless after only 1.5 million years. After the first millennia (1,000 years), the strands of DNA become far too short to read.
There are many variables to be considered, of course. As soon as a creature, say, a terrifying pterodactyl, passes on, everything in its body begins to die and decay. As cells die, enzymes begin to eat away at the nucleotide backbone of DNA as other micro-organisms speed the process along. Once only bone is left, groundwater becomes the worst enemy of any existing DNA, and though it can be a stubborn contender, DNA, just like the walls of the Grand Canyon, will eventually lose its fight with water. The speed at which groundwater destroys this DNA depends on variables such as temperatures, microbial attacks and oxygen, according to the team of palaeogeneticists.
Therefore, even under the best conditions, Dino DNA simply hasn´t been able to stand the test of time.
Simon Ho, a computational evolutionary biologist at the University of Sydney in Australia, breaks this finding down in a “Good News–Bad News” situation, saying first, “This confirms the widely held suspicion that claims of DNA from dinosaurs and ancient insects trapped in amber are incorrect,” speaking with Nature.com.
Even if we don´t get a Dino-themed amusement park, Ho does say the research was able to set a record. “We might be able to break the record for the oldest authentic DNA sequence, which currently stands at about half a million years.”
Another paleogeneticist for New Zealand, however, isn´t letting this research kill off the last shred of hope in his heart as he looks for other ways to make this dino DNA dream a reality.
“I am very interested to see if these findings can be reproduced in very different environments such as permafrost and caves,” said Michael Knapp with the University of Otago in Dunedin.
So, while the dream of bringing terrifying dinosaurs back to life may have died earlier than DNA stored in an amber-locked mosquito, at least we know we can at least bring back the Dodo bird, and that´s something, right?