Teeth reveal oldest genetic data of human ‘cousin’ Sciences

In the study Available onlinestill without a peer-reviewed publication, the authors indicate that the protein genetic material analyzed was extracted from dental fossils in Paranthropus robustus. The four specimens were found in Swarkrans Cave, located 40 kilometers from Johannesburg, the capital of South Africa.

the magazine natureKaterina Duca, an archaeologist at the University of Vienna, Austria, commented that the findings were “incredible”. “At such advanced ages it is common for remains to turn almost to stone,” said the specialist, who was not involved in the research.

The authors believe that the teeth were preserved due to an “extensive cementing” process in the cave. More than that, they hypothesize that the specimens were accumulated as a result of flash floods, with the possibility that the owners are not even from the same group.

To conduct the research, the team led by Enrico Cappellini used a mass spectrometer. This technique made it possible to analyze the hundreds of amino acids in the tooth enamel of each of the samples present.

In this way, it was verified that there are many proteins in the mineral layer of the teeth. Among them, amelogenin-Y, which is produced by a gene on the Y chromosome. Its presence in two samples suggests to specialists that they belong to male individuals.

The other teeth showed no signs of Y amelogenin. Instead, they contained the X chromosome version of the protein, leading the authors to conclude that the samples were probably female.

In total, about 400 amino acids were sequenced in the four samples. This allowed the researchers to build a simple evolutionary tree Homo sapiensAnd Neanderthals and Denisovans are more closely related to each other than to humans Paranthropus sp. Therefore, although they share the same evolutionary heritage, they are more like “distant cousins”.

Building an evolutionary tree from the genetic data of these discoveries “can be seen as a potentially transformative advance for paleoanthropology,” Cappellini and colleagues write in the paper. They argue that studies of ancient proteins can pave the way for new discoveries.

But not everyone agrees with the effectiveness of this technique. Currently, the order of the human family tree depends on the shape of the bones found. For example, says Pontus Skoglund, a paleontologist at the Francis Crick Institute in England, nature The study of mitochondrial DNA is more reliable than the study made of proteins. “The analysis of ancient evolutionary proteins still has a long way to go,” he asks.