Evocation of DNA from the Blood Sample Mixed with Road Concrete- A Forensic Review

Abstract

Adiba Ansari, Naresh Kumar and Amit Chauhan

Several types of biological samples are recovered in different conditions in various types of crimes. Sometimes, due to mishandling of the evidence they do not produce good results. Blood is a common type of biological sample found at crime scene involving hitand-run, murder and various sexual assaults, etc. In the cases such as hit and run, the blood gets mixed up with the soil and act as resistance in obtaining proper DNA profiling of a victim or a suspect. The advanced technologies for DNA profiling like STR analysis help in the identification of a criminal even if there is not much quantity of biological sample from the crime scene. But non-scientific procedure of blood collection and preservation reduces the chances of amplification of DNA. Additionally, in many outdoor cases blood sample contaminated with soil becomes problematic because of the presence of humic acid in soil. Humic acid inhibits the amplification of DNA and leads to unsuccessful profiling of DNA. The inhibitors in the samples act as obstacle in the cases where blood is lifted from the surface of earth and lead to the unsuccessful DNA analysis. PCR artifacts like partial profiles, multi-peaks, or complete failure of DNA profile can be seen in STR profiles obtained from contaminated samples. In this study, we reviewed the blood samples recovered from different surfaces (wall of plaster, cemented floor pieces, black road concrete) over a period of 5 to 36 months. This study concludes that the sample containing less soil particles yield DNA higher than the samples containing high amount of soil particles.

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