Scientists at Murdoch University have shown that it is impossible to reconstruct dinosaurs from ancient DNA, with the new findings revealing that genetic material can’t survive beyond 6.8 million years.
The study has busted the myth in Steven Spielberg’s film Jurassic Park, showing that unlike the creative premise in the film, it isn’t possible to use fossilized DNA to clone dinosaurs. Most dinosaurs died out about 65 million years ago.
Dr Mike Bunce and Dr Morten Allentoft reached their finding after analysing carbon-dated bones from 158 extinct New Zealand moa birds. “It has been agonisingly difficult to estimate the rate of DNA decay before now because finding a large set of DNA-containing fossils with which to make meaningful comparison is exceedingly rare,” Bunce said. “The moa bones, however, have allowed us to study the comparative DNA degradation because they come from different ages from a region where they have all experienced the same environmental conditions,” he said.
The fossil bone specimens were carbon dated as being between 600 and 8000 years old. Looking at the varying degrees of DNA degradation in each specimen, the team was able to calculate a DNA half-life of 521 years. The half-life is the amount of time taken for an amount of DNA to reach 50 per cent of the starting amount. After estimating the decay rate in the specimens the scientists predict that DNA fragments will be preserved in frozen fossil for about 1 million years.
Bunce said environmental conditions like temperature, degree of microbial attack and oxygenation can affect the DNA decay process. Other factors that impact on DNA preservation include storage time following excavation, soil chemistry and even the time of the year when the animal died, he said.
The team said that much more research into DNA degradation was required because their findings showed that age of the fossils can account for only 38.6 per cent of the variation in DNA preservation. Bunce said they hope to refine predication of DNA survival to more accurately map how DNA fragments decay across the globe.