Evaluating the effectiveness of touch DNA method for criminal investigations in Zambia.

Touch DNA (trace DNA) is a forensic method for analysing DNA left at a scene of a crime such as shed skin cells and other biological material transferred from a donor to an object or a person during physical contact. This method of identification was pioneered by the British geneticist, Sir Alec John Jeffreys, who observed the similarities and distinguishing characteristics of DNA within a family in his lab in Leicester. The Zambian justice system has been making decisions to convict or exonerate crime suspects basing decisions on circumstantial evidence from either witnesses or confessions from the suspects after interrogation. This study aimed at establishing the potential application of touch DNA in criminal investigations in Zambia using established Short Tandem Repeats (STRs) from thirteen loci. DNA was extracted from twenty-one mobile phones which served to simulate crime scenes and twenty-one buccal swabs from participants which served as reference samples. DNA extraction was done using automated Qiacube Connect device, quantification was done using Rotor-Gene Q (Real-time PCR) followed by PCR-amplification while amplicons were sequenced by the Sanger dideoxy- chain-termination method in an AB 3500 xL Genetic Analyser. Of the twenty-one simulated casework samples, nineteen successful profiles were fully generated, while twenty DNA profiles from twenty-one simulated reference samples were successfully generated. A comparison of the results from simulated casework and reference samples established that touch DNA method could indeed be applied in forensic investigation in Zambia. The findings of this study support the suggestion that touch DNA could be incorporated in criminal investigations and could be used to link suspects to crime scenes in the country.