The growth of our teeth occurs day after day in streaks that appear from our birth – and sometimes even a little before – in the enamel and dentin. They provide information about the speed at which our teeth form. Visible in sections under a microscope, they can be detected using powerful X-rays such as those produced by the European Synchrotron Radiation Facility (ESRF) in Grenoble. This tool was used by an international team to analyze the development of the teeth of a representative of the genus. Homo. Found at the Dmanissi site, Georgia, the fossil dates back to approximately 1.8 million years ago. The results are presented in the magazine. Nature since October 14.
The first data was collected in 2006. “We found that the maturation of molar crowns was faster than anything known, in both chimpanzees and modern humans. It was so unexpected that we thought we were wrong.”says Paul Taffordeau of the ESRF, who conducted these analyses. Advances in the instrument and visualization tools have only confirmed the first results, prompting the researchers, after eighteen years of doubt, to present their results to their peers.
They determined that at the time of his death, individual D 2700/D 2735 from Dmanissi was just over 11 years old, approaching dental maturity, and had already erupted his wisdom teeth. A chronology close to what we observe in great apes such as chimpanzees. On the other hand, as in humans, the posterior teeth lagged behind in their development with respect to the front teeth. “This suggests that baby teeth were used for longer than in great apes [chez qui leur chute marque l’âge adulte]and that the children of Homo “The ancients relied on adult support for longer than the great apes.”explains Marcia Ponce de León (University of Zurich, Switzerland), co-author of the study, in a press release.
Scalable engine
The hypothesis is that this prolonged childhood – compared to that of the great apes – would have served to collect the knowledge transmitted by adults, parents and even grandparents. A phenomenon that would have occurred “before any substantial growth in brain size” of these hominids, the researchers write. Contrary to what is usually stated, they believe that it is not the growth of the brain that has caused the prolongation of childhood, but that it is this that has preceded and initiated it, through a phenomenon of “biocultural evolution.”
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