Detection of bone glue treatment as a major source of contamination in ancient DNA analyses

Abstract

Paleogenetic investigations of ancient DNA extracted from fossil material is for many reasons susceptible to falsification by the presence of more recent contamination from several sources. Gelatine-based bone glue that has been used extensively for nearly two centuries by curators to preserve hard tissues contributes nonauthentic DNA to paleontological material. This fact has been frequently neglected and is barely mentioned in the literature. Now paleogeneticists, curators, and conservators are faced with the problem that treatment of samples with adhesives and consolidants for conservatory purposes has seldom been recorded. Here, we show that racemization of amino acids, and in particular serine, is an excellent indicator for the treatment of paleontological samples with glue.

Contamination controls when preparing archaeological remains for ancient DNA analysis

“…3. If possible, avoid adding any preservatives to specimens as these chemicals may inhibit PCR amplifications and may cause potential contaminant DNA to adhere to the specimens [21]. 4.…”

Possible interferences of some conservation treatments with subsequent studies on fossil bones: A conservator’s overview

“…Traditional consolidants such as animal glues may cause confusion because they are based on animal collagen and they therefore contain foreign DNA. This may be misunderstood, especially if there is no treatment documentation (Nicholson et al, 2002). As for modern consolidants, they also seem to influence the success of DNA analyses.…”

“…It is important not only to record the treatments conducted on a sample, but also to ensure that this information is passed on to the researchers studying that sample. In fact, some of the studies mentioned were aimed precisely at detecting whether or not the bones were previously consolidated (Nicholson et al, 2002), while others refer to the difficulty of working with collections which may have been treated with consolidants but do not have detailed documentation (Tuross and Fogel, 1994). The documentation should always specify the consolidant product used, including its trade name and composition and the method of application.…”

Biochemical and physical correlates of DNA contamination in archaeological human bones and teeth excavated at Matera, Italy

“…Importantly, this also includes studies of pathogen DNA in ancient samples, which may be at risk from DNA originating from environmental organisms [14], as well as studies on animal bones that have been treated with preservatives and glues containing animal DNA [31]. Furthermore, the results suggest that, if such contamination persists within 'cleaned' samples, even the adoption of authenticity criteria (e.g.…”