Gordon Turner-Walker

DNA in ancient bone – Where is it located and how should we extract it?

Despite the widespread use of bones in ancient DNA (aDNA) studies, relatively little concrete information exists in regard to how the DNA in mineralised collagen degrades, or where it survives in the materials architecture. While, at the macrostructural level, physical exclusion of microbes and other external contaminants may be an important feature, and, at the ultrastructural level, the adsorption of DNA to hydroxyapatite and/or binding of DNA to Type I collagen may stabilise the DNA, the relative contribution of each, and what other factors may be relevant, are unclear. There is considerable variation in the quality of DNA retrieved from bones and teeth. This is in part due to various environmental factors such as temperature, proximity to free water or oxygen, pH, salt content, and exposure to radiation, all of which increase the rate of DNA decay. For example, bone specimens from sites at high latitudes usually yield better quality DNA than samples from temperate regions, which in turn yield better results than samples from tropical regions. However, this is not always the case, and rates of success of DNA recovery from apparently similar sites are often strikingly different. The question arises as to whether this may be due to post-collection preservation or just an artefact of the extraction methods used in these different studies? In an attempt to resolve these questions, we examine the efficacy of DNA extraction methods, and the quality and quantity of DNA recovered from both artificially degraded, and genuinely ancient, but well preserved, bones. In doing so we offer hypotheses relevant to the DNA degradation process itself, and to where and how the DNA is actually preserved in ancient bone.

The West Runton fossil elephant: A pre‐conservation evaluation of its condition, chemistry and burial environment

Abstract The state of preservation, future stability and research potential of an important fossil find from the Pleistocene (the West Runton fossil elephant) were investigated using scanning electron microscopy, chemical analysis and ‘experimental ageing’ techniques. Results of these analyses indicate that although pyritic minerals are present in the fossil material, the bones are stable when stored in appropriate environmental conditions and that treatment for pyrite decay is unnecessary and undesirable. This finding, in part, reflects the geochemistry of the deposits in which the fossil elephant were found. In general the fossil skeletal material was found to be well preserved albeit structurally weakened by loss of collagen. In line with current thinking on the treatment and handling of sub‐fossil bones, consolidation should be restricted to vulnerable or badly fragmented areas. A limited pilot study of suitable cleaning procedures for the fossil material was undertaken and suggested that localised ai...