Plotted are (a) the number of endogenous DNA fragments recovered from the three reagents and full lysis of bone powder aliquots, (b) the percentage of DNA fragments that could be identified as endogenous by mapping to a reference genome, (c) the amount of collagen retrieved from bone powder expressed as the percentage of the starting mass, (d) the carbon content (%C) and C: N ratio (horizontal line) of the collagen preparation, and (e) uncalibrated AMS radiocarbon dates obtained from treated and untreated bone powder aliquots in years before present (BP).
Error bars in panels a-d denote the standard deviation (±1σ) computed from technical replicates.
EDTA is carbon-rich and synthesized from sources that contain only stable carbon isotopes (“old” carbon, .
However, the fossil record is often scarce and fragmentary, not only at Paleolithic sites, which limits the amount of material that can be sacrificed for molecular analyses.
More importantly, every effort possible should be taken to keep destructive sampling to a minimum in order to preserve the world’s archaeological heritage for future generations.
Therefore, the biomolecules required for radiocarbon dating and ancient DNA analysis are presumably located in different fractions of the bone matrix, suggesting that it might be feasible to retrieve both from a single sample by targeting the inorganic and organic components of the bone/tooth matrix separately.
Such a combined method for DNA and collagen extraction would not only reduce the number of samplings and thereby the amount of material required to perform both techniques, but also substantially increase the amount of material available for genetic analyses.
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.