Here's how it works. Until the 1990s, the only sure-fire way to establish the identity of an individual was to examine his or her fingerprints. That is because each individual's fingerprints have a unique pattern. Now, DNA is rapidly becoming the method of choice when it comes to linking individuals with crime scenes and criminal assaults.
Most people know that our inherited characteristics come from chromosomes and genes.
Now, as the end of the century rapidly approaches, we are on the verge of learning which genes result in which characteristics. While this knowledge promises untold rewards in the treatment of disease, agricultural production and an understanding of life itself, it is also being used as a means to uniquely identify individuals and to link individuals to criminal activities. Different methodologies allow experts to identify these distinguishing elements. DNA evidence is also proving to be a powerful tool in determining the innocence of prisoners who were tried before DNA testing in its current form was an option. If bodily samples, such as blood or semen, were collected from the crime scene or victim and that evidence is still available for DNA testing, a showing that the prisoner's DNA doesn't match the crime-scene DNA can be a powerful reason to conclude that the prisoner is innocent and should be released.