Small things in perspective: the contribution of our blind tests to micro-residue studies on archaeological stone tools

Our blind tests are distinctive for they were conducted on replicated stone tools used for a variety of tasks that included the processing of animal remains and plants. The analyst was required to differentiate an array of residues from microscopic morphological characteristics, using light microscopy. The original aim of our first tests was to assess the analyst's ability to identify a variety of plant and animal residues, but issues and problems that arose during the testing process made it clear that greater value might be gained from the lessons that we learnt about methodology and the direction for future micro-residue research. We show that problems identified during our first tests stimulated research. Amongst other things, we learnt to distinguish plant and animal remains more confidently than previously. Our residue analyses are firmly embedded in wider archaeological research and our tests help to explain why there are sometimes contradictions between the evidence from archaeologically recovered remains and residues on stone tools. A further outcome of the tests is that we have adopted a multi-stranded approach that provides a cautious, but secure strategy for identifying and interpreting use-residues. Our studies of contaminants through replications have also been invaluable for distinguishing incidental residues from use-related residues.     

A Polluting Concept of Culture: Native Artefacts Contaminated with Toxic Preservatives

This research examines the practical and theoretical fallout of the toxic methods used by museum conservators to preserve native artefacts and regalia. These conservation practices, dating to the late 19th and early 20th centuries, were undertaken before the age of museum professionalisation and within a larger context of cultural assimilation. Many of these chemical preservatives produce the same harmful effects in humans as they do in the organisms they were designed to eradicate. As these contaminated artefacts are repatriated, members of native communities who attempt to reintegrate them into ceremonial and daily practice are put at significant health risk. Not only do these pollutants undermine the stated goals of repatriation but they also stand as a literal instance of the way in which a hegemonic and interpreting culture has metaphorically contaminated the culture it has purported to preserve and display.     

An improved PCR method for endogenous DNA retrieval in contaminated Neandertal samples based on the use of blocking primers

Neandertal skeletal remains are usually contaminated with modern human DNA derived from handling and washing of the specimens during excavation. Despite the fact that the distinct Neandertal haplotypes allow the design of specific primer pairs, for instance in most of the mitochondrial DNA (mtDNA) hypervariable region 1 (HVR1), the human contaminants can often outnumber the endogenous DNA, thus preventing a successful retrieval of Neandertal sequences. We have developed a novel PCR method, based on the use of blocking primers that preferentially bind to modern human contaminant DNA and block their amplification, and greatly improve the efficiency of Neandertal DNA retrieval. We tested the method in four El Sidrón Neandertal samples (two teeth and two bone fragments) with different contamination levels and taphonomic conditions, and we have been able to significantly increase the Neandertal yield from figures around 25.23% (5–69.6%) up to 90.18% (75.3–100%).     

Chemical and Mineralogical Alteration of Ceramics from A Late Bronze Age Kiln At Kommos,Crete: the Effect On the Formation of A Reference Group

The formation of reference groups comprises an important procedure in chemical provenance studies of archaeological pottery. Material from ancient kilns is thought to be especially suitable for reference groups, as it comprises a definite unit of past production. Pottery from the Late Minoan IA kiln excavated at Kommos, Crete was analysed in order to produce a reference group in this important area of Minoan ceramic production. The samples were characterized by a combination of techniques providing information on the chemistry, mineralogy and microstructure of the ceramic body. Initially, the study was unable to establish, in a straightforward manner, a chemical reference group. Different ceramic pastes and a range of selective alterations and contaminations, affected by variable firing temperatures and burial environment, were shown to be responsible for the compositional variability. Procedures are described to compensate for such alterations and the perturbations in the data that they produce.