DNA

Michael J. Spence and Demosthenes Lorandos

Demosthenes Lorandos, Ph.D., J.D.

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 this Forensic Use of DNA chapter 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: 

Population statistics, probability, likelihood ratios and error rates 

Challenges in interpreting DNA, including the various forms of bias  

DNA extraction 

DNA, generally, its use and how it’s gathered in criminal investigations 

DNA in sexual assault cases, including examination collection 

Evidence examination, including illumination, photography &microscopy, and body fluid analysis 

Chain of custody and evidence prioritization, storage and processing 

Human errors, including sample mislabeling and switching and cross-contamination 

Limitations, misinterpretations and misrepresentations 

DNA amplification

Real-world examples and vignettes of DNA falsification and contamination catastrophes 

 DNA quantification

 History of the development of the forensic use of DNA 

Comparing evidentiary DNA with known DNA sources  

Use of DNA databases in cold casework and wrongful conviction reversals 

DNA transfer events, mixtures and residential effects 

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.