The effect of eraser sampling for proteomic analysis on Palaeolithic bone surface microtopography

Virginie Sinet-Mathiot,Jean-Jacques Hublin,Rosen Spasov,Frido Welker,Tsenka R Tsanova,Naomi L Martisius,Adam Van Casteren,Geoff M Smith,Ellen Schulz-Kornas,Nikolay Sirakov

doi:10.1038/s41598-021-02823-w

Abstract

Bone surface modifications are crucial for understanding human subsistence and dietary behaviour, and can inform about the techniques employed in the production and use of bone tools. Permission to destructively sample such unique artefacts is not always granted. The recent development of non-destructive proteomic extraction techniques has provided some alternatives for the analysis of rare and culturally significant artefacts, including bone tools and personal ornaments. The Eraser Extraction Method (EEM), first developed for ZooMS analysis of parchment, has recently been applied to bone and ivory specimens. To test the potential impact of the EEM on ancient bone surfaces, we analyse six anthropogenically modified Palaeolithic bone specimens from Bacho Kiro Cave (Bulgaria) through a controlled sampling experiment using qualitative and 3D quantitative microscopy. Although the overall bone topography is generally preserved, our findings demonstrate a slight flattening of the microtopography alongside the formation of micro-striations associated with the use of the eraser for all bone specimens. Such modifications are similar to ancient use-wear traces. We therefore consider the EEM a destructive sampling approach for Palaeolithic bone surfaces. Together with low ZooMS success rates in some of the reported studies, the EEM might not be a suitable approach to taxonomically identify Pleistocene bone specimens.

Highlights

Bone surface modifications are crucial for understanding human subsistence and dietary behaviour, and can inform about the techniques employed in the production and use of bone tools
We observe a systematic absence of peptides of higher molecular weight, in particular markers COL1α2 454–483, COL1α1 586–618 and COL1α2 757–789, which are absent in all eZooMS spectra, and COL1α2 793–816 present in one spectra (Supplementary Table S3 + Supplementary Fig. S5)
The signal-to-noise ratio (S/N) of the three dominant peptide markers (COL1α1 508–519, COL1ɑ2 978–990, and COL1ɑ2 484–498) of the eZooMS samples show, in the case of COL1α1 508–519, COL1ɑ2 978–990, lower to similar values compared to the bone samples with the exception of specimen CC7-1530

Summary

Introduction

Bone surface modifications are crucial for understanding human subsistence and dietary behaviour, and can inform about the techniques employed in the production and use of bone tools. The recent development of non-destructive proteomic extraction techniques has provided some alternatives for the analysis of rare and culturally significant artefacts, including bone tools and personal ornaments. Such assignments are not necessarily c orrect[19], and lack taxonomic precision To overcome these obstacles, researchers are using biomolecular approaches like palaeoproteomics, in particular Zooarchaeology by Mass Spectrometry (ZooMS)[20,21], ancient DNA analysis, and high-resolution CT scanning of bone histological thin sections to assess raw material selection and behavioural aspects associated with the artefact[22,23]. The Eraser Extraction Method (EEM) is one of the non-invasive strategies called “eZooMS” (electrostatic ZooMS) and has recently been extended to various archeological materials such as bone and ivory[25,37,39]

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Discussion

Conclusion