Radiocarbon dating ams
Additionally, the first testing of the samples was successful, yet analysis of the dates proved inconclusive.
AMS measurements will be performed again to obtain better sampling statistics in the hopes of narrowing the reported date ranges.
Since carbonates in the mineral fraction of hard tissues are exchanged with those present in the environment, in which a first treatment with hydrochloric acid solubilizes carbonates and hydroxyapatite, the main inorganic component of bones and teeth, a second treatment with sodium hydroxide removes other organic molecules such as humic acids, and a third treatment with hydrochloric acid removes atmospheric carbon dioxide absorbed during the base treatment.
The resulting collagen is then incubated in acid at high temperature to produce soluble gelatine.
One method to determine the artwork's age is radiocarbon dating via Accelerator Mass Spectrometry (AMS) performed at the University of Notre Dame's Nuclear Science Laboratory.
Samples are prepared by combustion of a small amount of material and subsequent reduction to carbon into an iron powder matrix (graphitization).
Here we explored the feasibility of releasing DNA from ancient bones prior to collagen extraction using an ABA-gelatinization procedure followed by ultrafiltration.
More specifically, we tested three reagents that might enable the recovery of DNA without degrading the organic component of the bone/tooth matrix.
Using a set of 12 bones of different ages and preservation conditions we demonstrate that on average 89% of the DNA can be released from sample powder with minimal, or 38% without any, detectable collagen loss.
These included the recovery of high-quality genome sequences from a Neanderthal, as well as a Denisovan individual, a type of extinct hominin so far discovered only at this site, neither of which required more than 40 mg of bone material, most recently from as little as 10 mg of powder removed from a milk tooth discovered at the site, which was shown to belong to a Denisovan individual based on the analysis of 1 million base pairs of its nuclear genome.
Both destructive methods, DNA analysis and radiocarbon dating, are invaluable tools for reconstructing past events and their timing, such as the colonization of Europe by anatomically modern humans (AMH) and Neanderthal extinction.
To determine whether it is feasible in principle to extract DNA and collagen from the same sample material without affecting radiocarbon dates, we used a dentistry drill to remove 7 g of powder from a 300-year-old horse bone (sample A) close in age to the upper limit of radiocarbon dating, and 8 g of powder from a C isotopes (see Table 1 and Supplementary Table S1 for details on the samples used in this study).
The powder from each sample was split into 500 mg aliquots, which were then either subjected directly to collagen extraction and dating, or incubated with EDTA, neutral, or acidic phosphate buffers to release DNA (see Fig.