Carbon dating material
By comparing the number of endogenous DNA fragments recovered during initial DNA release to those obtained from subsequent full lysis of the same bone powder aliquots, we estimate that EDTA released 42% and 99% of the endogenous DNA from samples A and B, respectively, while acidic phosphate released 53% and 50% (Fig. In contrast, no more than 20% of the endogenous DNA was released by incubation in the neutral phosphate buffer from either sample. While the size distributions of DNA fragments retrieved from EDTA and neutral phosphate were similar, acidic phosphate showed an enrichment for short DNA molecules (Supplementary Fig. Prompted by these results we performed binding experiments of DNA to hydroxyapatite and bone powder, and found that when compared to long molecules, short molecules are both more efficiently released from hydroxyapatite by acidic phosphate and more efficiently retained from acidic buffers during subsequent silica-based DNA purification (Supplementary Figs S2 and S3).DNA recovered from this buffer also showed a severe decrease in the relative abundance of endogenous vs. Comparing the suitability of EDTA, neutral and acidic phosphate treatments for DNA release prior to collagen extraction and radiocarbon dating.This is achieved by releasing DNA from the bone matrix through incubation with either EDTA or phosphate buffer prior to complete demineralization and collagen extraction utilizing the acid-base-acid-gelatinization and ultrafiltration procedure established in most radiocarbon dating laboratories.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.
More specifically, we tested three reagents that might enable the recovery of DNA without degrading the organic component of the bone/tooth matrix.
1a for a schematic overview of the experimental design).
Following DNA release, half of the aliquots were used for collagen extraction and dating, and half were incubated with an EDTA/proteinase K buffer commonly used in ancient DNA extraction to achieve full lysis of the bone powder and release any residual DNA.
Over the past 70 years, radiocarbon dating has become an important tool for archaeology due to its precision in dating organic material up to approx. The wide-spread use of radiocarbon dating has been facilitated by the use of accelerator mass spectrometry (AMS), which determines the .
Carbon isotopes isolated from collagen are the primary source used in radiocarbon dating of bones and teeth, and current protocols require approximately 500 mg of bone or dentine with a minimum of 1% preserved collagen, providing insights into the history of human groups, their dispersals and interactions.