DNA fingerprinting on trial: the dramatic early history of a new forensic technique

The effectiveness of the UK national DNA database

Since the emergence of forensic DNA profiling and the corollary creation of DNA databases, efforts to maximise the efficiency and utility of DNA technology have intensified. Such efforts are expedient given the imperative that expenditure on DNA should be cost-effective and the benefits demonstrable. The practice of retaining DNA profiles in databases, either obtained from individuals involved in criminal investigations, or retrieved from suspected crime scenes, has spread globally. The UK's National DNA Database (NDNAD), created in 1995, is both one of the longest established, and biggest of such forensic DNA databases internationally. As such, it is instructive to look at whether there is evidence to demonstrate the effectiveness of this DNA database. This paper thus examines efforts to gauge the effectiveness of forensic DNA databases, concluding that while the UK NDNAD may have led directly to convictions in high profile crimes, its broader impact upon public security goals remains elusive.

A retrospective study of sexual offences in Zambia

Zambia has recently reported high incidences of sexual abuse against women and children. Zambian law categorises sexual offences into rape, defilement, incest and others, with defilement constituting the majority of the reported cases (>89%). Between 2010 and 2012, convictions of defilement cases were achieved in only 13% of cases reported to the police. DNA evidence has shown prominence in resolving crimes, specifically as an identification tool in sexual offences. Currently there is no empirical evidence describing the role of forensic evidence in sexual crimes in Zambia; as such a retrospective study was conducted to evaluate this between 2007 and 2014 (n = 1154). Only 14 (0.1%) of the cases had forensic samples collected in the form of a vaginal swab for semen analysis. In all cases where a suspect was identified (60%), identification was based on the witness/victim testimonies, and in no case, was forensic DNA evidence used to assist in identification or corroborate the testimonies. Overall, 28.1% of cases were taken to court and the conviction rate was 12.4%. These findings support the use of employing DNA evidence in sexual offence cases to aid the identification of suspects, which is hypothesised to increase the number of cases prosecuted in Zambia.

An overview of DNA typing methods for human identification: past, present, and future

This chapter presents a brief introduction to the historical development of current technologies used in DNA analysis for human identification. The text describes the development of the PCR and short tandem repeats along with subsequent advances in instrumentation such as real-time PCR and capillary electrophoresis. These techniques have brought about a revolution in DNA typing methods through increased efficiency and the application of multiplex fluorescence detection. More recently the development of new STR based typing methods utilizing mini- and Y-STR PCR multiplexes has increased the flexibility of the investigator, permitting the analysis of inhibited and degraded DNA. Future directions for DNA typing are also discussed, including the development of methods for touch samples based on low copy DNA analysis and the determination of tissue/cell type.