As fate would have it, two papers came out from the PalaeoChron team on the same day! The first paper released concerned our work at the Salkhit site in Mongolia. This was led by Thibaut Devièse and Dijendo Massilani (Max Planck Institute for Evolutionary Anthropology. This work focused on an enigmatic robust hominin cranium from Mongolia (left). We worked on this with our colleague Seonbok Yi from Seoul. We re-dated the specimen to 34,950 – 33,900 years ago; around 8,000 years older than the initial radiocarbon dates obtained on the same specimen. To make this discovery, we used our new optimised technique for radiocarbon dating of heavily contaminated bones by extracting the amino acid hydroxyproline (HYP). Dating this amino acid allows for the drastic improvement in the removal of modern contaminants from the specimens. Our colleagues in the MPI-EVA in Professor Svante Pääbo’s group reconstructed the complete mitochondrial genome of the specimen. It falls within a group of modern human mtDNAs (haplogroup N) that is widespread in Eurasia today, confirming the view of some researchers that the cranium is indeed a modern human. Further nuclear DNA work is underway to shed further light on the genetics of the cranium.
The second paper, which came out a few hours later in Nature, was focused on the key site of Denisova Cave in Siberia. This paper was led by Katerina Douka and the result of more than 5 years of work at the site with our Russian collaborators. Denisova is the only site in the world known to have been occupied by both archaic human groups (hominins) at various times. We obtained 50 new AMS dates from the site and to determine the most probable ages of the archaic hominin fossils, we developed a novel Bayesian modelling approach that combined several of these dates with information on the stratigraphy of the deposits and genetic ages for the Denisovan and Neanderthal fossils relative to each other. The latter was based on the number of substitutions in the mitochondrial DNA sequences. Nature included two papers on Denisova in the same edition yesterday. The other was led by Zenobia Jacobs and colleagues and focused on the optical dating of the site.
For more information on these papers go to the media pages on our site: