Effects of fingerprint development reagents on subsequent DNA analysis

Abstract

A variety of evidences are found at crime scenes. Fingerprint and DNA evidences are especially important in the process of identifying personal sources. Among evidences found at crime scenes, cigarette butts are important because they might contain both fingerprints and DNA. In this study, latent fingerprints were detected in cigarette butts using 1,8-diazafluoren-9-one (DFO) and 1,2-Indanedione/zinc chloride (1,2-IND/Zn). Next, DNA extraction and real-time qPCR were performed to quantify and identify the DNA present. Short tandem repeat (STR) profiling was also performed. The results showed that the quantity of DNA recovered was decreased by 16% in DFO-treated cigarettes and by 27% in 1,2-IND/Zn-treated cigarettes when compared to untreated controls. When the STR profiling results were compared with those of the control sample, DFO, and 1,2-IND/Zn reagent-treated DNA samples showed individualized genotyping at several loci. Results of this study showed that when cigarette butts were found, DFO and 1,2-IND/Zn reagents could be used for DNA profiling after fingerprint identification. However, the effect of DFO on STR profiling was less than that of 1,2-IND/Zn. Therefore, we recommend the use of DFO for fingerprinting cigarette butts if further DNA processing is planned.