The role of DNA evidence in criminal proceedings

Abstract

The use of forensic evidence has been utilised in our criminal justice system for decades and has continued to develop immensely over the years. Technological advancements regarding DNA profiling techniques, such as the Restriction Fragment Length Polymorphism (RFLP) and the Short Tandem Repeat analysis (STR), have made it possible for DNA testing to become more accurate. DNA evidence can be used for multiple reasons such as the identification of the perpetrator and the extent to which they were involved in the crime. This dissertation seeks to understand the role of DNA evidence in criminal proceedings as well as the admissibility requirements of DNA evidence by comparing two jurisdictions, namely, South Africa and the United States of America. DNA evidence undoubtedly plays a massive role in our criminal justice system; however, it is not a perfect system without error as several problems could arise during the collection, testing or using of DNA evidence. Although there are several legislative provisions that have been established regarding the use of DNA evidence, factors such as the contamination of samples, mislabelling of samples, improper preparation of laboratory results and inadequately qualified field workers pose a threat to the quality of DNA evidence that is produced and handed to legal representatives to use in court and build their case. These problems often lead to miscarriages of justice which negatively impede the growth of our justice system as well as the rights of the accused to a fair trial. In addition, these issues raise questions concerning the reliability of DNA evidence and whether convictions based solely on DNA evidence are justifiable.