A recent toast to James Watson highlights a tolerance for bigotry many want excised from the scientific community.
Researchers measure how long it takes for DNA from bone to degrade, confirming that genetic information from dinosaurs could not last to the present day.
October 11, 2012|
Few researchers ever believed that DNA could survive long enough to make Jurassic Park a reality, and yet there have been no reliable models for how long the molecule takes to degrade. But a study published this week (October 10) in the Proceedings of the Royal Society B estimates that DNA from bone has a half-life of 521 years: after that amount of time, half of the nucleotide bonds that hold it together are broken, and after another 521 years, those bonds are cut in half again, and so on.
To determine this rate of decline, an international team of paleogenetisicts examined DNA samples from 158 leg bones belonging to three species of Moa, extinct giant birds from New Zealand. The bones ranged from 600 to 8,000 years old, but all had been preserved in almost identical conditions, which meant the researchers could make comparisons between the ages of the specimens and the state of the DNA.
Based on their calculations, the team predicted that even under perfect conditions for DNA preservation, it would take a maximum of 6.8 million years for every bond to be destroyed. And even before that time—after around 1.5 million years—the remaining strands of DNA would be too short to be readable. So a dinosaur bone, which would be at least 65 million years old, could never yield useable genetic information.
“This confirms the widely held suspicion that claims of DNA from dinosaurs and ancient insects trapped in amber are incorrect,” Simon Ho, a computational evolutionary biologist at the University of Sydney, Australia, who was not involved in the study, told Nature.
October 11, 2012
Poiner's work with ancient weevils compared DNA sequences from extant beetles to the DNA from his and from my recollection, there was very good correspondence. What were the problems with that methodology? Hopefully, there is a library somewhere of those sequences to compare in a fuller sense to make sure that it wasn't all contamination.
October 11, 2012
Were these DNA samples extracted from bones fresh from the soil or from museum pieces. Horner's and Poiner's work shows that proteins/dna swiftly decays after a fossil is taken from the ground. How can this information say anything about DNA decay in amber? I dare to say DNA is much better preserved in amber then in bones.