Comparison of Time Course Detection of Human Male DNA from Blood Stains on Various Objects on Surface in a Natural Environment and in a Laboratory Using Loop-Mediated Isothermal Amplification (LAMP).

Abstract

In forensic study, the biological evidence can easily degrade, especially DNA. Degraded and environmentally challenged samples can produce numerous problems in forensic DNA analysis including loss of band product. Loop-mediated isothermal amplification or LAMP is one of the DNA analysis techniques used in forensic study. This study explores the limitations of the efficiency of the LAMP technique on abandoned DNA. For the DNA template, 8 male and 2 female blood-stained samples were taken from the surfaces, namely, brick, cloth, and tile from inside, and buried outside the laboratory. The LAMP reaction was used to amplify the SRY gene for detecting male DNA. All the blood-stained samples were stored for 1, 7, 15, 30, and 45 day (s). The LAMP product from the blood-stained samples on all the surfaces that were kept in a laboratory was detected using the gel electrophoresis technique from day 1 until day 45. However, the LAMP product on day 30 and 45 was smear and dim. The LAMP product from the blood-stained samples buried outside the laboratory was observed using the gel electrophoresis technique within day 30 (smear and dim). To increase the efficiency of detection, the qLAMP technique detected product on all the male samples from all the surfaces buried outside the laboratory for 45 days. The results indicate that this LAMP condition was possible detecting male DNA and the environmental factors are the main influence on the sensitivity of the LAMP technique. In addition, the qLAMP technique can increase the capacity and sensitivity of the detection.