Comparative Study of DNA Identification on Two Different Sexual Assault Cases

Abstract

Sexual assault or rape is one of many criminal cases that still occur daily in alarming numbers. Regarding in resolving many of these rape cases, forensic DNA testing has a major role in exonerating or convicting an individual deemed as suspect. Current DNA testing provides the DNA profile of evidence and reference through STR markers-based and lineage markers of Y chromosome and mitochondrial DNA approach. STR can distinguish an individual from another individual. There are two sets of STR markers complying with the standards requested by criminal databases around the world. These STR markers are mainly incorporated into commercial kits such as GlobalFiler™ Kit. This study aims to compare the processes and results of forensic DNA identification on two different rape cases. All samples were examined and extracted by chelex extraction method. The DNA extracted from these samples was quantified then amplified in 24 markers with GlobalFiler™ Kit and followed by capillary electrophoresis. Lastly, the DNA profile was compared and matched. Different samples from both cases yield a different amount of DNA concentrations with a very low level of male DNA concentrations in the vaginal swab. Therefore, it failed to produce any DNA profile. Full DNA profile on 24 markers of some samples was successfully obtained and compared, with one sample obtained a partial DNA profile. Two samples of each case are found to be biologically related because of the similarity in half of their DNA profile. One of the cases regarded as inconclusive because of the absence of the perpetrator’s DNA profile in the evidence. Thus, making it impossible to compare.