Even if scientists did not find a full skeleton, they were able to trace human DNA in some dirt and small remains in caves. This technology could help researchers reconstruct human evolutionary history. The new study was published on April 27 in the journal Science. Because fossilized bones, which represent the primary source of ancient DNA, are rarely discovered to be well-preserved even in places where there is evidence of prehistoric human presence.
- Researchers are now able to identify human DNA even if they do not find any bones.
- They improved a technique used for animal and plant DNA tracking to uncover human DNA in sediment samples.
- In those caves, scientists also identified some stone artifacts and animal bones.
Matthias Meyer, a geneticist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, stated that scientists had discovered many caves where only tools were intact, but they could not find any human remains. Thus, researchers knew that they need to develop a method which could help them reveal human DNA from dirt samples.
They collected about 85 sediment samples from 7 different caves in Russia and Europe that were well-known for the fact that humans lived there between 14,000 and 550,000 years ago. Researchers improved a method which had previously helped them trace plant and animal DNA. In this way, they were able to uncover genetic material that belonged to ancient humans in the past.
Experts’ only purpose was to examine mitochondrial DNA coming from the maternal line. This material helped scientists differentiate related species. By observing damaged molecules, researchers managed to separate ancient genetic material from dirt particles and other contamination left there by modern visitors. After completing the analyses, scientists argued to have identified evidence of 12 mammal families including extinct species like cave hyena, cave bear, wooly rhinoceros and wooly mammoth.
Nevertheless, after enriching the samples for human-like DNA, researchers were able to trace genetic residues of Denisovans. This is known to be a lineage of ancient humans which were first discovered in a cave in Siberia. They also found traces belonging to Neanderthals at four different sites. One of the caves where they identified genetic residues of Neanderthal is located in Belgium. The cave was called Trou Al’Wesse. At that site, they did not found any human bones.
However, they unearthed animal bones and human artifacts which clearly suggested that some humans have visited that cave in the past. Eske Willerslev, who helped the team of researchers, noted that it was incredible to see how scientists identified human DNA in sediment samples, but, at the same time, the process was very complex.
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