Abstract

Genetic Identification has become an important forensic investigation method which discerns identity through analysis of physical samples discovered in various crime scenes. Recently more samples are being requested to undergo A-STR analysis of low copy number (LCN) DNA, which is known as touch evidence-type sample and left on various objects such as a pen briefly used by the criminal, the gear of the car used for driving, the handle, and various buttons inside a car. This research attempted to extract the LCN DNA of the touch evidencetype left on crushed fingerprints on firearms, etc. and examine the genotyping success rate. Four types of firearms (M16, K1A, COLT 45 Pistol, M29 Revolver) were fired individually and physical samples were gathered from four parts of each firearm. Subsequently, in order to extract the LCN DNA, Microkit and PrepfilerTM were used to compare and analyze the quantity of DNA extracted and the genotyping success rate. Analysis results showed that the quantity of DNA extracted by Prepfiler^(TM) was on average 1.7 times higher than that of Microkit, and in genotype analysis success rate Prepfiler^(TM) also demonstrated 24.9% on average in contrast to 0% for Microkit. In regards to the grip part of the K1A, Prepfiler^(TM)’s success rate was as high as 50.6%.