According to Dr David Penney and his colleagues at the University of Manchester, UK, the existence of ancient DNA in amber fossils is highly unlikely.
The idea of recreating dinosaurs by extracting DNA from insects in amber has held the fascination of the public since the early 1990s.
But Manchester University scientists in their new study, published in the open-access journal PLoS ONE, have revealed this technique is unlikely to succeed.
They used highly-sensitive sequencing techniques – the most advance type of DNA sequencing – on insects in copal, the sub-fossilized resin precursor of amber.
The study was conducted wearing full forensic suits in an ancient DNA facility, which comprises a suite of independent, physically isolated laboratories, each with an ultra-filtered air supply maintaining positive displacement pressure and a managed access system.
“In the original 1990s studies DNA amplification was achieved by a process called the polymerase chain reaction (PCR), which will preferentially amplify any modern, undamaged DNA molecules that contaminate an extract of partially degraded ancient ones to give false positive results that might be mistaken for genuine ancient DNA,” explained senior author Prof Terence Brown.
“Our approach, using ‘next generation’ sequencing methods is ideal for ancient DNA because it provides sequences for all the DNA molecules in an extract, regardless of their length, and is less likely to give preference to contaminating modern molecules.”
The scientists concluded that their inability to detect ancient DNA in relatively young – 60 years to 10,600 years old – sub-fossilized insects in copal, despite using sensitive next generation methods, suggests that the potential for DNA survival in resin inclusions is no better, and perhaps worse, than that in air-dried museum insects.
This raises significant doubts about claims of DNA extraction from fossil insects in amber, many millions of years older than copal.
“Intuitively, one might imagine that the complete and rapid engulfment in resin, resulting in almost instantaneous demise, might promote the preservation of DNA in a resin entombed insect, but this appears not to be the case. So, unfortunately, the Jurassic Park scenario must remain in the realms of fiction,” Dr Penney concluded.
Bibliographic information: Penney D et al. 2013. Absence of Ancient DNA in Sub-Fossil Insect Inclusions Preserved in ‘Anthropocene’ Colombian Copal. PLoS ONE 8 (9): e73150; doi: 10.1371/journal.pone.0073150