The phenomenon of using DNA from old fossils preserved in amber has long been a Hollywood trope. In Jurassic Park, scientists reproduce the DNA of dinosaurs extracted from a fossil mosquito embedded in a piece of amber, and thereby resurrect them.
In reality, however, the undertaking is much more difficult: all previous studies in which researchers took DNA samples from insects enclosed in tree resin were the results of modern environmental contamination and, in addition, were unreproducible, subsequently useless under the scientific method. But an international team led by researchers at the University of Bonn have now detected DNA from ambrosia beetles that was trapped in recent tree resin for less than 7 years.
Using so-called ancient DNA, scientists can draw conclusions about long gone times and the organisms living there. The use of organisms trapped in amber (fossil tree resin) with this finality was thought not to be possible after relatively recent fails in looking for DNA in a few thousand-year-old samples.
"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," explained study leader David Peris, a professor at the University of Bonn. The superordinate aim of the researchers is to develop step-by-step fundamental aspects of the DNA preservation in the resin and to determine the real temporal border-- the point at which DNA in resins remains preserved.
“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,” said Peris.
The resin samples used in the study, published in PLOS ONE, were 6 and 2-years-old and came from Madagascar. To extract the DNA, the scientists established a method based on PCR, which makes it possible to multiply genetic material in a test tube. This method is well-known in criminology and recently became famous, as the basic technology for the detection of the SARS-CoV-2.
“This method allowed us to perform several authenticity checks, so that we could say certain that the detected DNA in our experiments was indeed from the beetles preserved in the resin,” explains second author Kathrin Janssen of the Institute of Medical Microbiology, Immunology and Parasitology.
The researchers found that water was stored in the embedded samples longer than previously thought, which has a negative effect on the stability of the DNA. In the future, the scientists plan to gradually analyze older samples with more sensitive next generation sequencing methods.
"Investigating the time limit of DNA conservation and many other related issues is the aim of future experiments," said Janssen.
Republished courtesy of University of Bonn. Photo: Resin samples from Hymenaea trees in Madagascar with embedded ambrosia beetles. Credit: Georg Oleschinski/Universität Bonn