Forensic and Physical Evidence

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Abstract Forensic science is a very useful technique in the criminal justice system. A variety of forensic techniques are applied in the investigation of crime. Most noteworthy is DNA profiling which utilizes the comparison of crime scene DNA against the DNA of suspects. Other commonly used techniques include forensic toxicology, ballistic fingerprinting, forensic entomology and digital forensics. Key words: Forensic, DNA, criminal justice system Introduction Forensic science mainly involves the application of Molecular Biology to aid investigation in the criminal justice system. This technology has been facilitated by DNA (Deoxyribonucleic Acid), which is the genetic material of a cell. DNA is the blue print of an organism. Most of the DNA are located in nucleus (nuclear DNA), but a small amount of DNA can be found in mitochondria (mitochondrial DNA). Human DNA consists of about three billion base pairs and more than 99% of those bases are the same in all people. It is divided into functional units called genes, which carry all instructions, which make up our body. DNA is contained in the blood, semen, hair, skin cells, tissues, organs, muscle, brain cells, bone, teeth, saliva, mucus, perspiration, fingernails, urine, faces etc. Although human DNA is 99% to 99.9% identical from one individual to the next, DNA identification methods use the unique DNA to generate a unique pattern for every individual. Several repetitive sequences occur in DNA and their sequence is unique to each individual. Every cell in the body, whether collected from a cheek cell, blood cell, skin cell or other tissue, shares the same DNA. This DNA is unique for each individual (except for identical twins who share the same DNA pattern) and, thus, allows for identification if two samples are compared.Forensic Science via the use of Molecular Biology techniques have had various
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