Jurassic park: truth or fiction?
An international team of experts recovered the DNA of trapped beetles in samples of resin collected from 2013 to 2017 in the Madagascar forests, according to a study published in the journal Plos One. The study explores new limits of conservation of genetic materials in resinous samples, and counts on the participation of Xavier Delclòs, professor at the Faculty of Earth Sciences and member of the Biodiversity Research Institute (IRBio) of the UB.
The study is led by the experts David Peris, who got his doctoral degree at the UB under the supervision of Xavier Delclòs, and Kathrin Janssen, both from Bonn University (Germany). It is also signed by Enrique Peñalver, from the Spanish Mining and Geology Institute (IGME), and Mónica M. Solórzano Kraemer, from the Senckenberg Research Institute (Germany), among other experts.
Truth or fiction: DNA recovery of trapped organisms in amber
Recovering genetic materials from samples in fossil resins from millions of years ago is one of the big challenges in palaeontology. So far, all initiatives in the scientific community to recover the DNA of trapped living beings in copal or amber from thousands and millions of years ago did not provide any satisfying result.
According to Professor Delclòs, “the rock of organic origin that better preserves organisms from the past is amber. If you look into the remains of organisms inside resins or amber, you can see the bodies in three dimensions and all the characters are well-preserved. In particular, the resin keeps the exoskeletons of these arthropods very well –which are mainly formed by chitin– or the leaves from producing trees. However, internal organs usually decompose when the organism is included by the resin. If a molecule like DNA could be preserved over time, the container should be amber. Therefore, there is controversy to try and extract genetic material from dinosaurs –think Jurassic Park– inside the DNA preserved in blood-sucking insects from the Cretaceous”.
For how long could the genetic material be kept inside the resin?
In the study, the team set a strict protocol to guarantee the correction of results and therefore rule out potential mistakes that have led to scientific controversy in previous studies. This methodology allowed researchers to recover the DNA of ambrosia beetles and wood-boring weevils –trapped in Hymenaea verrucosa resin samples, gathered during the campaigns of 2013 and 2015. These samples were taken directly from the trees in Madagascar forests as part of different expeditions to study how resinous trees can originate amber sites with many trapped insects.
Despite the fragility of the genetic material, experts could detect the genetic material of beetles in the resin using the Polymerase Chain Reaction technique (PCR). Experts detected material in the beetle specimens of Mitosoma that were conserved in resin. According to David Peris, “this technique gave a lot of plasticity to cross-check and confirm that if we detected DNA in our specimens, it was from resin-preserved beetles”.
According to Enrique Peñalver, “we are completely certain of the device, since we used primers that start sequencing in genetic material only if the sample shows some specific genetic material of this type of beetle”.
The study sheds light on the study of temporary evolution of DNA degradation “to find the maximum time a resin can keep DNA from past organisms inside. The study confirms degradation goes fast, in just a few years, and that there are containers in the fossil records that allow the preservation of DNA much easily than resins (contrary to what was believed)”, notes Delclòs.
Researchers highlight the need to make more analysis with older resins –perhaps with new techniques– in order to establish the tie limits of conservation of such a molecule like DNA. “Therefore, we can say that Michael Crichton’s novel and the movie Jurassic Park are still fiction”, notes Xavier Delclòs.