“Only Cigarette Butt is Left, DNA Fingerprinting Traps the Theft”

Pawar Sg,Mahajan Kd,More Bp,Harel Vs,Kulkarni Kv

doi:10.15744/2348-9804.6.103

Abstract

The examination of saliva traces left on cigarette butts as evidences are complicated due to the availability of biological material in trace amounts and its rapid degradation due to extreme effects of environmental factors. This study is aimed to assess the DNA purity and quantify the amount of DNA preserved in saliva found on cigarette butts subjected to various temperatures and humidity. Isolation of cell material from biological traces on forensic evidence is often a serious challenge to solving forensic cases. Successful isolation of high-grade DNA from cell material even in critically low quantity could be achieved in examination of traces. The proper collecting and storage of the material is very important for successful DNA typing from saliva traces and epithelial cells from the lips and oral cavity. Meeting these conditions would increase the chances for successful DNA profiling of biological traces on evidence of an earlier date. In the presented forensic cases the opportunity for solving the crime was given by the vices of the suspects. In this case one cigarette butt found at scene of crime was the only evidence to detect the accused. DNA is extracted from salivary epithelial cells adheres to the cigarette butt and profiled successfully. DNA profiles of suspected accused and the cigarette butt are matched in the source.

Highlights

Cigarette butts are a common trace sample at crime scenes and obtaining DNA profiles from this evidence is an important capability in the forensic science repertoire
The DNA extracted from saliva detected on cigarette butt found at scene of crime and blood sample of suspect was typed at 15 STR LOCI and gender specific Amelogenin locus using polymerase chain reaction (PCR) Amplification technique
Table No.5 shows that the DNA profile obtained from saliva detected on cigarette butt found at scene of crime and DNA profile obtained from blood sample of suspect is identical and from one and same source of male origin

Summary

Introduction

Cigarette butts are a common trace sample at crime scenes and obtaining DNA profiles from this evidence is an important capability in the forensic science repertoire. DNA extraction is a critical step in forensic analysis because quality of DNA directly affects the ability to obtain a good quality forensic profile. Cigarette butts are notably difficult samples in that they produce DNA that is contaminated with inhibitors of the polymerase chain reaction (PCR) [1]. Most methods in current usage solve the problem by adding a series of post-extraction steps to selectively remove inhibitors. These steps make the method complex, non-automatable, susceptible to contamination, and the many steps reduce DNA yields – a critical factor with trace samples [1,2]

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Conclusion