For the first time, scientists have obtained fragments of DNA from beetles that were trapped in tree resin found in Madagascar.
Wealthy geneticists with dreams of a dinosaur-filled theme park should not get too excited, however. The trapped insects died just a few years ago. Nevertheless, the incredible new study shows that, after much speculation, it is possible to obtain and study the genetic makeup of organisms found embedded in tree resin.
"Instead of looking for DNA in amber of 100 million years old or more, to dream about the resurrection of dinosaurs, we should start by detecting it in insects trapped a few years ago in resin," David Peris, study author from the Institute for Geosciences and Meteorology at the University of Bonn, said in a statement.
"Our new results show that it is indeed possible to genetically study organisms that were embedded in resin, although we do not know the time limit yet,” he added.
Reported in the journal PLOS One last week, paleontologists and microbiologists from the University of Bonn in Germany got their hands on two samples of tree resin from a Hymenaea verrucosa tree in Madagascar that contained a number of ambrosia beetles (Coleoptera: Curculionidae) that became stuck in the resin when it was still gooey. The two samples were aged to around two to six years. After obtaining material from within the solid resin, they used a technique known as a polymerase chain reaction to multiply genetic material in a test tube, confirming their hopes that DNA fragments were still preserved in the resin-embedded organisms.
Previous attempts to gather genetic material from animals inside tree resin have used chloroform or 70 percent alcohol as part of the process of extraction. However, the researchers on this project realized this reacted with the resin and compromised the DNA. Instead, this new study saw the researchers opt for a slightly tweaked method that used over 80 percent ethanol and ensured the samples avoided any contamination from the modern environment.
Once again, the samples in this study are just a few years old, so it still remains unclear whether it's possible to apply this technique to older samples, let alone prehistoric samples. The study revealed that water appears to remain embedded in samples for longer than previously thought, which could have a negative effect on the stability of the DNA. Nevertheless, they hope to build on this project by finding an upper limit to how long DNA can last in tree resin using more sensitive "next-generation sequencing" methods.
"Investigating the time limit of DNA conservation and many other related issues is the aim of future experiments," summarized Kathrin Janssen, a study author from the Institute of Medical Microbiology at Bonn.