Determination of DNA profiling of siwak and toothbrush samples used in Kingdom of Saudi Arabia

Abstract

Background: DNA profiling is an integral part of forensic work. Enough and good samples for DNA quantification and profiling are mandatory.
Aim of the study: To quantify and profile DNA from siwak and toothbrushes and study the effect of time on this process.
Methodology: The present study included DNA profiling from siwak and effect of time on extracted DNA. Then; obtained data were compared to those extracted from toothbrushes. For this purpose, 25 uncovered siwaks, 4 covered siwaks, and 25 toothbrushes were used. Samples were divided into 8 groups; first group (4 months; 4 volunteers); second group (3 months, 5 volunteers); third group (2 months, 4 volunteers); fourth group (1 month, 5 volunteers); fifth group (1 week, 3 volunteers); sixth group (the same day, 4 volunteers and covered siwak was added); seventh group (reference samples) and group 8 (positive and negative control samples). Extraction of DNA was done using Promega kit and then PCR was used for amplification and DNA profiling was done.
Results: Considerable quantity of human genomic DNA was successfully extracted from siwaks. There was no proof of the existence of any substance in siwak or its components that may interfere with amplification of DNA by PCR or interfere with obtaining DNA profiles. Siwak proved to be a good and reliable source of human genomic DNA that is enough for DNA analysis. There has been no effect of time on DNA analysis and DNA profiling in this study (within the targeted period which is 4 months).
Conclusion: Siwak contains enough quantity of DNA, and retained good DNA profiling; and when compared to toothbrushes, siwak is a reasonable source of DNA profiling when found at the scene of crime. In addition, time of storage up to 4 months had no or little effects on results.