Forensic Use of DNA
DNA evidence has revolutionized the ability to identify individuals for a variety of uses, perhaps most notably in the criminal justice system. An elegant technology, DNA is not, however, (as some believe) infallible. Like all science that requires human action, DNA evidence is also subject to both errors and interpretive exploitations. It is the goal of Chapter 8 of the Litigator’s Handbook of Forensic Medicine, Psychiatry, and Psychology, Forensic Use of DNA, to provide a practical guide for attorneys and judges to help them distinguish reliable and valid DNA evidence from that improperly gathered, interpreted and opined upon. Particular topics include:
DNA, generally, its use and how it’s gathered in criminal investigations
DNA extraction
Comparing evidentiary DNA with known DNA sources
Chain of custody and evidence prioritization, storage and processing
Real-world examples and vignettes of DNA falsification and contamination catastrophes
Use of DNA databases in cold casework and wrongful conviction reversals
Population statistics, probability, likelihood ratios and error rates
Human errors, including sample mislabeling and switching and cross-contamination
Evidence examination, including illumination, photography µscopy, and body fluid analysis
DNA quantification
DNA amplification
DNA in sexual assault cases, including examination collection
Challenges in interpreting DNA, including the various forms of bias
Limitations, misinterpretations and misrepresentations
DNA transfer events, mixtures and residential effects
History of the development of the forensic use of DNA
To better illustrate the complex topics of this chapter, a multitude of vignettes are provided, that describe: (1) what DNA evidence looks like when it is properly gathered and admitted; (2) what it looks like when error, bias and contamination are allowed in evidence; and (3) the ruinous consequences that occur when active malfeasance plays a role in the production and use of DNA evidence.
An excellent guide for this difficult subject matter, the Forensic Use of DNA chapter is an invaluable resource for lawyers and jurists charged with responsibility for ensuring that any DNA evidence admitted is reliable and valid.
