Recovery of human DNA profiles from poached deer remains part 2: Improved recovery protocol without the need for LCN analysis
Introduction
Poaching occurs in most countries to some extent. It can include the taking of endangered species such as rhinoceros, elephant or tiger; or more common species such as deer, bear and moose. Poaching is generally considered a crime of opportunity and there is generally very little physical evidence left behind for forensic scientists.
The standard method of investigation of poaching incidents is to identify traces of the poached animal on, or in the possession of, a suspect [1], [2], [3], [4]. While this avenue of investigation is suitable if a suspect is identified, it cannot be used in cases where only the remains of an animal are discovered. Species that can be legally hunted with license or in season can complicate matters as it can be difficult to determine when the biological evidence was deposited. Individual identification of a poached animal is possible for some species (e.g. mule deer [3] and wolf [5]) and can provide a link between evidence and a carcass, but these tests are highly specialised and are not available for all species (e.g. roe deer). Development of these non-human STR tests is also expensive and time consuming [6], meaning that they tend to be adapted from other studies and may not be suitable for forensic purposes. Further, specialised animal testing (very few laboratories are equipped to handle animal evidence and those that are will generally charge accordingly), means that this method of investigation requires large amounts of resources. Poaching incidents can be seen as a ‘victimless crime’ and many police forces are not willing to expend the resources for investigation, especially as more serious types of crime are highly publicised.
A method to investigate poaching is required that does not require large amounts of resources. We previously reported on the successful recovery of human DNA from simulated poached deer remains [7]. This holds many benefits over current methods, the most notable being that rather than animal DNA being the focus of identification, human DNA is used. Other benefits include: no specialist protocols are needed; the techniques are used daily in forensic science laboratories; recovered profiles can be searched against a database; the science is accepted in court and is understood by the legal community; and the resulting profiles are of high probative value.
Personnel, equipment and time resources are minimised as only one (or two if corroboration is required) forensic scientist(s) are needed to sample the carcass, and the sampling protocol requires only four mini-tapes making it quick and cheap [7]. The sampling process can even be delegated to wildlife officers or charity workers, with proper training, if allowed by the legal system of the country/region. As no specialist non-human DNA testing is required, the cost is significantly reduced and the value of the evidence is increased.
Although a significant step forward in tackling wildlife crime, the use of low copy number (LCN) analysis in the previously describe technique [7] meant that it could not be applied in all areas due to the specialist LCN protocol. LCN analysis also increased the cost of the testing, although not as much as specialist non-human analysis. In order to remove the need for LCN analysis and reduce the cost, we now describe an optimised recovery protocol and analysis method that does not require the use of the LCN protocol. This makes the test available to all forensic science laboratories without any increase in cost from standard DNA analysis, while at the same time increasing the number of recovered alleles and loci.
Section snippets
Materials and methods
All deer samples used in this study were obtained as part of an annual cull. No animals were harmed directly for the purpose of this research. The deer used in this study were Roe Deer (Capreolus capreolus). Details of collection kits, sample collection and contamination control are as previously described [7].
Results and discussion
We previously demonstrated successful recovery and amplification of human DNA from simulated poached deer carcasses [7]. The mini tapes from the original feasibility study, as well as the new samples used in this study, had blood and hair from the deer, as well as dirt and detritus from the environment, attached to the adhesive surface. This led to an expectation of high amounts of deer DNA, from the blood and hair, compared to low levels of human DNA, from epithelial cells.
We hypothesised that
Conclusions
Although poaching is a regularly encountered type of wildlife crime, the high and prohibitive cost of specialised animal testing means that many cases are left un-investigated. We previously described a novel approach to wildlife crime investigation that looked at the identification of human DNA on poached animal remains [7]. We have significantly improved on this method in the current study; removing the need for LCN analysis and increasing the recovery success rate. Benefits of this modified
Acknowledgements
Funding for this project was provided by Scottish Natural Heritage, Deer Commission for Scotland, The British Association of Shooting & Conservation, The British Deer Society, Royal Society for the Protection of Birds and with the support of PAW Scotland. We would also like to thank MOD Deer management who were essential in gathering the samples, Mrs Rosemarie Wilcock DE Ops North Deer Operations Manager, Jim Conroy DDM District Coordinator Scotland and volunteers from the Scottish DDM groups.
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