Question

How can DNA evidence be used to convict or exonerate a defendant? Why is DNA evidence so powerful?

Answer 1

Answer: DNA evidence offers the criminal justice a powerful tool for convicting the guilty and exonerating the innocent. DNA exemplify the blueprint of the human genetic framework, existing in virtually every cell of the human body and differs in its nucleotide sequences (i.e A,T,G,C). Human genome is composed of three billion nucleotides, which are 99.9% identical among individuals. 0.1% variation, of these nucleotide sequences can be used to discriminate one individual from another. It is this difference that can be exploited to match specimens of blood, bone, hair, and other body tissues and products obtained through criminal investigation as evidence, to an individual with a high level of certainty. DNA printing has transformed the forensic science and its approach towards criminal investigations. However, the technical reliability of DNA evidence depends on a number of factors including human error, contamination and degradation of DNA samples during collection of evidence. Though such disadvantages and implications of DNA fingerprinting are rare, in majority of cases it has successfully contributed to the identification of criminals, as well as exoneration of the accidentally accused.