The Importance of DNA Evidence
What is DNA? Is it these winding strands that look like ladders or is it what gives a person blonde hair and blue eyes? Actually, DNA is both of these things. DNA is a person’s genetic makeup–their hereditary blueprint passed on by their parents. It is a part of almost every cell in the human body. In each cell, a person’s DNA is the same; it stays the same throughout their lifetime. DNA is found in skin tissue, sweat, bone, the root and shaft of hair, earwax, mucus, urine, semen, and vaginal or rectal cells. The DNA found in a person’s saliva is the same as the DNA found in their blood. Parts of the DNA determine our physical characteristics, such as eye and hair color, height, and bone structure, but the DNA collected from the crime scene is for evidentiary purposes only and not to determine an assailant's physical characteristics. (Turman) Originally, DNA profiling was developed as a method of determining paternity. Samples taken under clinical conditions were examined for genetic evidence that could link parent to child. DNA evidence was first introduced to courts in England in 1986, when a molecular biologist was asked to verify the confession of a suspect. Alec Jeffreys, the molecular biologist, had begun investigating the use of DNA forensics and aided English police in excluding a 17 year-old boy as a suspect in two rape-murders. The tests proved the teenager was not the perpetrator and the actual attacker was eventually caught, also using DNA testing. In the United States, the first DNA-based conviction occurred in 1987 when Tommy Lee Andrews was convicted of rape by the Circuit Court in Orange County, Florida. Andrews’ DNA test from a blood sampled matched the DNA of semen traces found in a rape victim. Two years later in West Virginia, the first state high court ruled in favor of admitting DNA evidence. (Cormier) In criminal investigations, DNA has proven to be a powerful tool. Since no two people, excluding identical...
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