A collection of 47 human teeth was excavated from a single stratigraphic layer of the cave site, and the researchers used a combination of zoological and geological evidence to date this layer to between approximately 80,000 and 120,000 years old. A calcific floor that formed after deposition of the remains sealed the layer from contamination with fossils from later periods. Uranium–thorium dating of a stalagmite showed that this floor was laid down around 80,000 years ago. Morphological analysis and radiocarbon dating indicated that mammalian fossils found in the same layer were from the late Pleistocene, providing an upper age limit for the stratum of around 120,000 years.
Previous studies of human remains from this period, found in the Levant, showed that these hominins retained primitive features. This observation supported the hypothesis that early human migration from Africa was unsuccessful and did not contribute to modern populations. By comparing the morphology of the Daoxian teeth to those from contemporary humans and other late Pleistocene human specimens, Liu et al. were able to demonstrate that the Daoxian fossils were more similar to European than to African or Asian late Pleistocene specimens and in many ways closely resemble present-day teeth. Therefore, not only were the Daoxian undoubtedly modern, but they probably lived at a time when more primitive populations occupied other parts of China. This finding suggests the existence of multiple origins or migration routes for modern human populations across Asia throughout the late Pleistocene period.
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