Confirmation of assassin from exhibits left at crime scene and its comparison with control sample of suspects using APoB primer

Author Name: Md Shahbaz Alam*,A.K Gupta, Archana Tripathi
Author Email: 1kshindwi@gmail.com

Abstract

DNA finger printing is a powerful technology for individualization of a person. In Forensic Science it has been used since three decades giving absolute results. In present study an effort has been made to extract and isolate DNA from exhibits like chewing gum and socks that were left at assumed crime scene and consequently the control samples were taken from the suspects. The DNA has been isolated and then amplified by using APoB primer, resulted in the formation of specific band pattern which was supportive in interconnecting the link of suspects with murder. It has been concluded from the present paper that the evidences collected from scene of crime containing saliva and sweat even in trace amount can be utilized as reliable sources for the identification through PCR-VNTR analysis.

Keywords

PCR-VNTR Forensic Science, DNA Isolation, Polymerase Chain Reaction, APoB primer, Hyper Variable Region.

Introduction

DNA fingerprinting is the most often used technology in the identification of an individual or living organism as used by Forensic Individuals. Every living creature is genetically different. Each individual contains a unique sequence which is specific to that organism. Unlike traditional fingerprints which can be surgically altered or self mutilated, the DNA sequence cannot easily be changed once the material is left at a crime scene, thus increasing its effective use in forensics, and the probability of finding an exact match.
It has been evident that Variable Number of Tandem Repeats (VNTRs) is highly polymorphic markers. Each VNTR locus since associated with a large number of different allele, each allele corresponding to a specific number of repeated sequences in any population. Each individual carries two allele only –one on each of two homologous chromosome. The important methodological merits of VNTRs are that its pattern is unique for every individual. [1-3]. Due to highly polymorphic character VNTR can be used as an important tool in forensic identification and comparison. They also constitute preferred system for ‘DNA Fingerprinting’, the direct practical application of which includes criminal and forensic examination, in solving the problem of identification amongst a large number of suspects.
VNTRs have been described as 73 base pair (b.p) 3’ to the second polyandenylation signal of the human ‘Apolipoprotein B, (APoB) gene (which is located on chromosome 2) and is commonly referred to as APoB 3’HVR (Hyper Variable Region) [4-6]. APoB 3’-HVR alleles and genotype have been much studied in numerous population. DNA isolated from biological materials can be analyzed by DNA profiling to help establish the source of deoxyribonucleic acid (DNA) [7-8]. It has been demonstrated that blood, semen, hair root, tissues, and bones are a good source of DNA for identity testing [9-11]. Sweat is also a useful material in this respect. These biological materials recovered from crime scene rely primarily upon the identification of blood group, antigens and rarely on iso-enzyme and polymorphic protein. These approaches have several inherent limitations, especially their limited detect-ability because of the low concentrations of antigens, isoenzymes and proteins in the samples. In addition to these, drying, aging, and contamination associated with this sample limit the number of markers that can be typed. The potential for discrimination using these markers are also less sensitive than DNA analysis.
This paper is focused on the present well known methods of identification based on VNTR analysis. The exhibit i.e. chewing gum and the sock bearing the saliva and sweat recovered from the crime scene was used to isolate DNA. The characteristic banding pattern obtained has been utilized for identification of offender involved in the murder case.

Conclusion

Biological fluid play a vital role in the field of forensic science for identification and comparison of suspected and control sample. The biological fluid normally left at the scene of crime during committing crime.DNA isolation from such fluids is a major challenge for Forensic biologist since these evidences contain tiny amount of biological material. It is necessary to use a suitable and appropriate method for extraction and isolation of DNA from different biological source using reliable methods, because once the sample utilized wrongly it can’t be used again .The DNA sample are very much sensitive to cross contamination, hence the use of appropriate primer for DNA typing is necessary to form a definite interpretation of result. APoB is a universal primer found in almost every individual but with different base pair length. In the present study APoB primer was used to solve a murder case which gave a trustworthy result. From this study it was concluded that APoB locus can be used in forensic science for identification of criminals in almost every cases.

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