DNA in Amber Doesn't Last Long
Claims of ancient DNA hundreds of thousands of years old may be false. No DNA was found in an insect encased in amber said to be 10,600 years old.
The article on Science Daily suggests that a study published in PLoS ONE puts the “final nail in the coffin” of Jurassic Park’s thesis that dinosaurs could be reconstructed from fossilized DNA in amber. Researchers from the University of Manchester looked for DNA in Colombian copal, the resin precursor of amber. Using “sensitive next-generation methods”, they obtained sequences a few hundred bases in length, but could not match them to the insects. They concluded, therefore, that they are artifacts. The abstract states,
We were therefore unable to obtain any convincing evidence for the preservation of ancient DNA in either of the two copal inclusions that we studied, and conclude that DNA is not preserved in this type of material. Our results raise further doubts about claims of DNA extraction from fossil insects in amber, many millions of years older than copal.
David Penney said that despite expectations that copal or resin would protect the DNA, providing an ideal environment for preservation, that doesn’t appear to be the case. “So, unfortunately, the Jurassic Park scenario must remain in the realms of fiction.” They couldn’t even find it in a specimen said to be 60 years old.
Update 9/18/13: Nature reported an alleged discovery of DNA from bones of a cave bear 300,000 years old extracted from permafrost. Most of the segments were less than 50 base pairs long, “too degraded” to be useful except with new techniques used by researchers at the Max Planck Institute. They claimed to assemble and sequence segments as short as 30 base pairs.
So what will this mean for claims of ancient DNA extracted from specimens said to be millions of years old? The obvious answer is that it’s not really that old. According to these scientists looking at insects under ideal conditions of preservation, 10,600 years is an upper limit. For the cave bear bones, it becomes less credible to believe permafrost conditions were uninterrupted for that long, let alone the question if permafrost is 30 times better at preserving DNA. How could that be tested without assuming the evolutionary dates?