Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.491690
Title: Development and Application of Forensic Genetic Typing Systems for Wildlife Species
Author: Dawnay, Nick
Awarding Body: Bangor University
Current Institution: Bangor University
Date of Award: 2008
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Abstract:
Wildlife forensic genetic science is the application ofmolecular techniques to legal investigations involving animal species. Despite being recognised as a useful approach in criminal investigations from the late 1980's, it remains a niche field with research and casework being performed by both trained forensic scientists and academic specialists alike. While human forensic research can be used as a basis for non-human forensic study, there is a lack offormal forensic recommendations and guidelines in the field which inevitably leads to different practices being adopted. This thesis examines the issues currently associated with wildlife forensic research and casework in the three areas associated with the field; species identification, population assignment and individual identification. An assessment of the utility ofthe mitochondrial DNA (mtDNA) marker cytochrome c oxdase I (COl) was undertaken in the form of a forensic validation study. The COl gene has been chosen as a marker for 'DNA barcoding' and the planned expansion ofthe COl database to include reference sequences for all known and newly discovered life would benefit forensic species identification. Validation results demonstrate that sequence similarity searches provide high percentage matches between unknown sample and reference sequences and are suitable for identification purposes where adequate reference sequences exist. A simulated case study reveals that the mtDNA cytochrome b (cyt b) marker performs better than COl due to the larger number ofcyt b species sequences that currently exist. The use of this marker together with cyt b will increase the strength ofgenetic evidence in casework requiring species identification. Where species cannot be differentiated using mtDNA markers, nuclear markers may be employed in conjunction with population assignment tests. Saker (Falco cherrug) and gyr (Falco rusticolus) falcons are currently classified as separate species and receive different levels ofinternational protection. Both species are subject to international trade controls (CITES) and the need for accurate identification for trade monitoring purposes is necessary. The results presented here demonstrate that both species share mtDNA COl haplotypes and display a paraphyletic relationship making these species indistinguishable when using this marker. However, the allele frequencies ofnine nuclear short tandem repeat (STR) loci are variable enough to identify the two species with >98% certainty. Despite the high certainty of identification, population assignment techniques such as this are currently limited to monitoring illegal trade and not useable for providing forensic evidence for casework. This is due to the lack ofvalidation associated with assignment tests and future work needs to address this shortcoming. The forensic identification ofindividuals in non-human species has received increasing attention in the last 10 years. While this attention has mainly focussed on commercial and domestic species there is also a need to identify wild individuals. Using the protected Eurasian badger (Meles meles) and six protected raptor species (golden eagle, Aquila chrysaetos, goshawk, Accipiter gentilis, merlin, Falco columbarius, peregrine falcon, F. peregrinus, gyr F. rusticolus and saker falcon F. cherrug), STR loci were validated and screened in representative populations of each species. Validation results suggest that all loci are usable for generating STR profiles in forensic casework although the typing systems in gyr and saker falcons require additional loci to increase their discriminatory ability. This research suggests that the match probability equation allowing for estimates of population substructure (8) and inbreeding if) is currently the most appropriate estimator for individual identification in wildlife species although further work will need to formally assess this.
Supervisor: Not available Sponsor: Not available
Qualification Name: Bangor University, 2008 Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.491690  DOI: Not available
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