DNA analysis and its application to forensic investigations at the victorian institute of forensic medicine

Abstract

The use of DNA analysis has become an integral part of forensic investigations, with many forensic laboratories relying on DNA to assist with criminal investigations as well as the identification of deceased persons. Since the late 1990 s, the Victorian Institute of Forensic Medicine (VIFM) has provided DNA identification services for deceased persons to the Coroners Court of Victoria (CCOV), utilising nuclear DNA (nDNA) and/or mitochondrial DNA (mitDNA) in its analysis. Imperative to DNA analysis is not only the type of sample collected, but also the manner in which the sample is collected and ultimately processed. Through years of experience, the VIFM has optimised sample collection and analysis methods to achieve a high success rate for DNA profiling. In addition, the VIFM has developed standard operating procedures to minimise contamination during the collection of samples destined for DNA analysis during post-mortem examinations, as well as during the analysis process itself. nDNA analysis, in particular short tandem repeat (STR) analysis, is routinely used at the VIFM to generate DNA profiles for deceased persons and reference samples to assist in familial matching, and hence assist in the identification of the deceased person. The STR analysis is performed on 16 loci (15 autosomal and 1 sex determining loci) which provide sufficient discriminatory power to enable familial or kinship matching. In addition, the VIFM is accredited to perform mitDNA analysis for forensic applications. mitDNA is inherited through the maternal line, so unless a mutation has occurred, siblings and all maternal relatives share the same mitDNA sequence. Human mitDNA is comprised of a small circular genome (16,569 bp) that contains highly variable regions with sufficient variation to enable human identification. Its robustness has led to its use as a reliable forensic tool; in recent times enabling the analysis of human remains from casualties of war or mass disasters. Whilst it is not as informative as nDNA analysis, mitDNA is very useful when sufficient quantities of nDNA cannot be extracted for a case, be it from bone, teeth or decaying tissue. In recent years, mitDNA analysis has been used to assist in coronial case investigations ranging from missing persons, where putative mother/child relationship have been discounted or affirmed by mitDNA analysis, to homicides. Discussed will be the application of DNA analysis to forensic investigations at the VIFM to assist with coronial case and police investigations, from sample collection through to analysis. The use of DNA analysis has become an integral part of forensic investigations, with many forensic laboratories relying on DNA to assist with criminal investigations as well as the identification of deceased persons. Since the late 1990 s, the Victorian Institute of Forensic Medicine (VIFM) has provided DNA identification services for deceased persons to the Coroners Court of Victoria (CCOV), utilising nuclear DNA (nDNA) and/or mitochondrial DNA (mitDNA) in its analysis. Imperative to DNA analysis is not only the type of sample collected, but also the manner in which the sample is collected and ultimately processed. Through years of experience, the VIFM has optimised sample collection and analysis methods to achieve a high success rate for DNA profiling. In addition, the VIFM has developed standard operating procedures to minimise contamination during the collection of samples destined for DNA analysis during post-mortem examinations, as well as during the analysis process itself. nDNA analysis, in particular short tandem repeat (STR) analysis, is routinely used at the VIFM to generate DNA profiles for deceased persons and reference samples to assist in familial matching, and hence assist in the identification of the deceased person. The STR analysis is performed on 16 loci (15 autosomal and 1 sex determining loci) which provide sufficient discriminatory power to enable familial or kinship matching. In addition, the VIFM is accredited to perform mitDNA analysis for forensic applications. mitDNA is inherited through the maternal line, so unless a mutation has occurred, siblings and all maternal relatives share the same mitDNA sequence. Human mitDNA is comprised of a small circular genome (16,569 bp) that contains highly variable regions with sufficient variation to enable human identification. Its robustness has led to its use as a reliable forensic tool; in recent times enabling the analysis of human remains from casualties of war or mass disasters. Whilst it is not as informative as nDNA analysis, mitDNA is very useful when sufficient quantities of nDNA cannot be extracted for a case, be it from bone, teeth or decaying tissue. In recent years, mitDNA analysis has been used to assist in coronial case investigations ranging from missing persons, where putative mother/child relationship have been discounted or affirmed by mitDNA analysis, to homicides. Discussed will be the application of DNA analysis to forensic investigations at the VIFM to assist with coronial case and police investigations, from sample collection through to analysis.