Extracting DNA from Ancient Amber Remains a Distant Ambition
Extracting DNA from ancient amber, a technique used in the fictional film Jurassic Park to recreate dinosaurs, is something that brings great difficulty to science. Although interesting, this scenario is utopian, and the only possible DNA extraction, for now, is that carried out in more recent amber, known as copal, as was the case in the study carried out by researchers at the University of Bonn, in Germany, still very recently.
Derived from a vegetable resin, amber went through several distillation processes until reaching the final result of a fossilized crystal, as explained by professor Luiz Eduardo Anelli, from the Institute of Geosciences (IGc) at the University of São Paulo (USP). He also comments that the material is confused with crystallized plant sap, but amber is produced, most of the time, in the bark.
“This amber contains substances, texture and density that help the plant heal wounds. It is a healing substance, a self-healing that the plant does. It often gushed out and formed a large mass and the animals got stuck, or it came loose from the trunk, fell and ended up in the water or on the forest floor and involved some material,” he says. The teacher also says that the gem gains even more value when it has an animal or plant inside.
According to Anelli, amber can be found all over the world and of different ages, with the oldest found being around 300 to 350 million years ago, from the Carboniferous period. “After that, we now find, from the Mesozoic Era, amber from the Triassic Period, from the first dinosaurs. In large volumes, it trapped material, so we can see some insects and small animals that lived with the first dinosaurs”, he adds.
The expert also comments on other famous ambers, such as those found in Lebanon, around 120 million years old, in Myanmar, around 100 million years old, and in Russia, with more than 400 tons of amber found per year. According to the professor, there are only microscopic ambers in Brazil, determining only small protozoa inside.
With advanced ages, ancient ambers are very important for the study of the history of the planet, capable of discovering everything from characteristics of very ancient animals and plants to the atmospheric composition of the time, or even diseases found in contaminated blood inside mosquitoes and other parasites preserved in these gems. “Amber is the golden sarcophagus, the most spectacular and precious tomb we could have. In a way, he traveled from that time to the future and we get to know what existed there. It is the most sophisticated machine that nature has invented, it is a window that we open and see the prehistoric world that no other rock was able to show’, concludes Anelli.
DNA extraction and use in biology
According to Maria Mercedes Okumura, professor at the Biosciences Institute (IB) at USP, the macroscopic preservation of the elements found in amber is good in many cases, as the resin quickly envelops the structures, causing a type of mummification. This allows studies from a biogeographical, behavioral and evolutionary point of view, in general.
“We can study the distribution of a given group of plants or animals according to the region and chronology associated with the presence of these resins, we can also describe extinct species and relate these species with living species, we can try to understand the evolution of a given group of organisms comparing the morphology of what is found in ancient amber with what is found in nature today”, he exemplifies.
Regarding the extraction of DNA and other biomolecules from organisms preserved in amber, Maria warns about the reality and fiction presented in the film Jurassic Park , in which scientists extracted the DNA of dinosaurs from mosquitoes preserved in amber, which would have sucked the blood of prehistoric animals. “In real life, scientists have tried to extract DNA not from the potential dinosaur blood that would be in the mosquito’s stomach, but from the mosquito itself, to use this example. Although this idea seems good, the preservation of DNA and other biomolecules in structures found in amber is far from satisfactory, since we have a major problem of possible contamination by recent DNA,” she explains.
Furthermore, there is a debate about the legitimacy of works that claim to achieve this feat, since, due to the small structure of the samples, destroyed in the initial analysis and without allowing the material to be analyzed in another laboratory, there is a serious limitation of the replication of your results. Maria states that, apparently, there seems to be the possibility of recovering DNA from structures preserved in resin, but much more recent than those from millions of years ago, still called copal — as was the case in the study carried out by researchers at the University of Bonn.
“This does not mean that the study of these structures preserved in amber is not important from a genetic point of view, but it is important to draw attention to the numerous challenges that involve this type of research. And here comes the role of scientists who, currently, have been working on these topics, have been proposing protocols and procedures for carrying out these studies, so that we continue to develop techniques that can generate knowledge about these genomes or pieces of very old genomes, without We run the risk of being very careless, generating false results”, he concludes.