Archaeological collagen: Why worry about collagen diagenesis?

By R. Dobberstein, Matthew Collins, Oliver E. Craig, G. Taylor, K. Penkman, Stefanie Ritz-Timme. 2009

151 citations recorded by the source corpus.

DNA appears to decay by random chain scission resulting in a predictable range of fragment lengths. Collagen decay has also been modelled in this same way, although it has become increasingly evident that collagen decay does not follow this same pattern. Radiocarbon and stable isotope analysis now use ultra-filtration to isolate large fragments (>30% of original polymer length) even in Pleistocene bone. How then does collagen decay? This study contrasts experimentally degraded samples with collagen extracted from forensic, archaeological and fossil bone. In experimentally degraded bone, values for amino acid and elemental (C:N) composition, bulk δ 13C, δ 15N, and aspartic acid racemisation (AAR) changed very little until 99% of the collagen was lost, suggesting that the collagen triple helix and polypeptide chains remained remarkably intact. This suggestion was demonstrated directly by examining the integrity of individual polypeptide chains using cyanogen bromide (CNBr) cleavage followed by SDS-PAGE electrophoresis. In ancient samples, AAR values remain remarkably stable and the pattern of CNBr-cleavage was only replaced with a smear of smaller polypeptides in the oldest (Pleistocene) bones investigated. Smearing may reflect both modification of the methionine resides (the sites of CNBr-cleavage) and/or partial hydrolysis of the collagen molecule. The findings reveal why it is not usually necessary to worry about collagen diagenesis; it is mostly intact. However, evidence of partial deterioration of the oldest bone samples suggests that alternative purification strategies may increase yields in some samples.

Subfields: Anthropology, Archeology, Paleontology

View Paper: https://www.semanticscholar.org/paper/b913163079adaaad4e3644fe2da9e303d59c6e04

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In Anthropology

1. Benjamin Thomas
2. Fiona Brock
3. K. Jurkschat
4. V. Geoghegan
5. P. Szpak

In Archeology

1. E. Guiry
2. Benjamin Thomas
3. Fiona Brock
4. K. Jurkschat
5. V. Geoghegan
6. T. Higham
7. P. Szpak

In Paleontology

1. E. Guiry
2. Benjamin Thomas
3. Fiona Brock
4. K. Jurkschat
5. V. Geoghegan
6. T. Higham
7. P. Szpak

Citations in the corpus

• Quality control for modern bone collagen stable carbon and nitrogen isotope measurements (2020, methodology): “…there has been relatively little research on the effect of selective amino acid loss on the isotopic composition of ancient collagen (although see, Dobberstein et al., 2009), low levels of collagen deterioration that do not result in large shifts in C:NAtomic are thought to have minimal impact…”
• Fish bone chemistry and ultrastructure: implications for taphonomy and stable isotope analysis (2011, background): “As such, additional controlled studies on the influence of various diagenetic processes (e.g. Dobberstein et al., 2008, 2009; Harbeck and Grupe, 2009) on the bones of mammals, fish and birds would be extremely beneficial.”
• Analysis of Bone “Collagen” Extraction Products for Radiocarbon Dating (2013, background): “However, Dobberstein et al. (2009) hypothesized that this could also be indicative of cross-linking in archaeological bones, resulting in modified chain lengths and poor electrophoresis.”