DNA Identification

Between 1892, when law enforcement officials first chose to use fingerprinting, and the late 20th Century, the population of the world increased greatly. That increase caused a decline in the reliance on fingerprinting. It also caused a rise in the interest in DNA identification. Scientists had shown that DNA identification proved more useful than fingerprinting. It offered law enforcement officials with a better way to identify the perpetrators of a crime. Once the public had finally come to understand the techniques that are used to carry out a DNA analysis, such analyses had become an accepted part of the judicial process.

In order to fully appreciate the value of DNA identification, one must first recognize the fairly recent appearance of the fingerprinting process. Law enforcement first chose to use fingerprints to identify criminals in the year 1892. In all the years prior to that, law enforcement officials had had to rely heavily on witnesses and on circumstantial evidence. Then for close to 100 years, the law enforcement community based its charges largely on fingerprint evidence.

Unfortunately, not all crimes gave the criminals a way to place their fingerprints on a surface from which they could be readily removed.  In addition, many criminals became adept at committing crimes without leaving any fingerprints. Thus, by the late 20th Century, the need for a better sort of identifier became apparent. In other words, the law enforcement community was looking for something such as DNA identification.

Now it so happens that the late 20th Century also introduced the world to the discipline known as molecular biology. The molecular biologist studied the various genetic structures of living things. One molecular biologist had developed a way to examine the exact biochemical make up of specific genes. Another scientist had designed a way to increase the amount of material that could be used in such an analysis. Therefore, the scientific community had laid the groundwork for DNA identification.

During the final decade of the 20th Century, the scientific community focused its efforts on something called “The Genome Program.” They wanted to determine the exact genetic make-up of various living organisms, especially humans. This program showed that all humans have 99.9% of the same genetic material. Only 0.1% of the genetic material in each human being is unique to that individual.

What does that mean for DNA identification? It means that of the 3 billion pieces of genetic information in the human genome, only 3 million pieces are unique to any one individual. Unfortunately, 3 million represents no small number. That is why DNA identification poses such a challenge.

Law enforcement officials have met that challenge by choosing to study selected genetic sites. They look at selected sites of variation and selected sites where DNA repeats are known to exist. Law enforcement officials rely on lab evidence, evidence acquired through use of the available analytical methods. That evidence has been introduced in the courts during specific court cases.

Those cases included one high-profile case, the case against O.J. Simpson. Although the DA could not convince the jury that the DNA at the crime scene matched that of the accused, that trial allowed the public to become more familiar with DNA identification. Since then a number of TV programs have provided the public with even more information about the methodology that allows the use of DNA in identifying a criminal.