DNA Evidence and Crime Solving
DNA evidence can be useful in both crime solving and in obtaining a conviction. DNA evidence is a form of physical evidence, in which DNA found at the scene of a crime is tested against the DNA of a possible criminal. DNA evidence is considered strong evidence since DNA tests are over 99% accurate when performed properly by a qualified lab.
What is DNA Evidence?
DNA is the part of all cells that contains the genes inherited from parents. Although people who are related often have similar DNA, even identical twins don’t have exactly the same pattern. As a result, DNA can be a unique identifier – much like a fingerprint.
Since DNA is in every cell in our bodies, evidence from the scene of the crime such as a piece of hair, a fingernail or some blood will contain the DNA of persons who were there. This commonly occurs in both rape and murder trials where a criminal may leave behind skin cells in the victim’s fingernails or other types of DNA cells. Forensic scientists are then able to extract a DNA profile by testing the evidence.
Using DNA Evidence to Solve Crimes
DNA evidence left at the scene of a crime can be run through databases of criminal DNA to determine if it matches any DNA on file. Some law enforcement agencies have begun to take DNA samples from all suspects arrested in a crime, thus creating a database of DNA similar to that of fingerprints. There is political controversy surrounding this practice, as some believe it is a violation of privacy. However, law enforcement officials and advocates believe this is no more an invasion of privacy rights than fingerprinting, and the Supreme Court upheld the practice.
DNA Evidence and Guilt
When a criminal is arrested for a crime, DNA evidence can also be used to prove his guilt. Due to high accuracy rates, DNA evidence is often considered to be highly persuasive proof of guilt. It has also been used to exonerate criminals, both for new crimes and for older crimes in which convictions occurred before DNA testing was available.
DNA Evidence in Family Law
DNA evidence is also used to prove paternity in family law cases. Since DNA is derived from parents, a DNA test can be used to determine whether there are similarities between a suspected father and the child whose paternity is in question. DNA tests are often considered to be more reliable then blood tests, which can only rule out a man and cannot definitely declare that he is in fact the father of the child in question.
Reliability of DNA Evidence
DNA testing is becoming more reliable with new advances in technology. Some labs claim to have an accuracy rating of over 99.99% accuracy, especially when multiple tests are performed to determine a DNA match.