DNA Fingerprinting :


I INTRODUCTION
DNA Fingerprinting, use of a person's body samples as a means of identification. Deoxyribonucleic acid (DNA) is a genetic blueprint found in the double strand or “double helix” of molecules called chromosomes located within the cell nuclei of all living beings. With the exception of identical twins, the complete DNA of each individual is unique.
In order to obtain a DNA “fingerprint”, DNA is first extracted from body tissue or fluid such as blood or saliva. Areas of DNA that can be used to distinguish one individual from another are segmented and arranged. Probes are used to mark the segments and X-ray film is placed on the probes and developed to form a pattern of black bars—the DNA “fingerprint”. DNA “fingerprints” are then compared for similarities.


II USES OF DNA FINGERPRINTING
DNA testing was originally developed for medical purposes in order to detect the presence of genetically inherited diseases. DNA fingerprinting, or DNA typing as it is often called, was first developed as an effective identification technique in 1985. The uses of DNA fingerprinting have expanded to include criminal investigations and forensic science. DNA fingerprinting was first used in a criminal investigation in the United Kingdom in 1987.
DNA evidence has a variety of applications in criminal investigations and forensic science. DNA evidence can confirm someone as a suspect to a crime by comparing DNA specimens found at a crime scene to a suspect's DNA. DNA evidence can also be used to exonerate a suspect.


III THE ADMISSIBILITY OF DNA EVIDENCE IN COURTS
Generally, courts have accepted the reliability of DNA testing and have admitted DNA test results into evidence. However, there have been criticisms of DNA fingerprinting for investigative or forensic purposes.


A
Accuracy of Results The accuracy of DNA fingerprinting has been challenged. First, because DNA segments rather than complete DNA strands are “fingerprinted”, there is a possibility that DNA samples taken from two individuals may yield identical results. For this reason, a finding that DNA fingerprints are identical is accompanied by the probability that the particular DNA pattern could appear in a particular segment of the population. As yet, widespread research confirming the uniqueness of DNA fingerprinting test results has not been conducted. In addition, because humans interpret the results there is always a possibility that mistakes will be made.


B
Prohibitive Costs Because DNA testing is expensive, suspects who are unable to provide their own DNA experts may not be able to adequately defend themselves if charges are brought against them based on DNA evidence and DNA experts are not provided for them. Furthermore, experts hired to testify either in support of or in opposition to the accuracy of DNA evidence may be biased.


C
Misuse of Results DNA fingerprint results may be used for unauthorized purposes such as to identify individuals with certain stigmatizing illnesses such as Acquired Immune Deficiency Syndrome (AIDS). The potential for misuse increases if DNA fingerprint results are databased.