DNA : Criminal Identification
Validity and Doubts
DNA, although controversial on accuracy, has provided a new means of
identifying criminals where there is little physical evidence. This allows you to take a
piece of hair, a spot of blood, or skin tissue and make a positive identification on a
suspect. Since it’s first use by the FBI in December 1988 it has grown to become a major
factor in criminal investigation. This new key gives them help when the crime scene
lacks evidence. DNA evidence also allows detectives to narrow down suspects and keep
innocent people from being prosecuted.
In 1990 the FBI began development of a national DNA identification
index. The FBI has received over 10,000 submissions of DNA evidence from police
agencies and DNA evidence has been used in over 500 cases throughout the United
States. The FBI performs testing for free to all police agencies to help keep costs down
in prosecuting criminals. More than 50 laboratories perform DNA analysis around the
US. The chances of two people having the same DNA profile is 1 in 50,000 all the way
to 1 in 5 million according to scientists estimates.
DNA controls all our inheritable information like eye color, hair color,
skin color, etc. DNA differs in all people except for identical twins. All cellular matter
contains DNA: this includes white blood cells, bone cells, tissue cells, spermatozoa, and
hair root cells. Adenine, thymine, guanine, and cytosine are the building blocks of DNA
strands which make up the letters of a genetic code. In certain regions of a DNA strand
the sequence of genetic code is unique which allows scientists to identify an individual
and exclude others.
The FBI, Cellmark, and Lifecodes are the 3 major laboratories that courts
accept DNA profiles from. As estimated by the FBI, the chances of two DNA samples
being the same is as low as one in a trillion. Critics of DNA say that the FBI has falsely
applied theories of population biology behind it’s calculations, so courtrooms make DNA
seem inaccurate. More than half the states have a mandatory DNA testing of all people
convicted of sexual charges and violent offenses, to help in future criminal investigations.
Although some people say that this is an invasion of privacy, it’s a good way to prosecute
repeat offenders and find suspects when only DNA evidence is available.
As accurate as DNA profiling is, there are still many questions about the
validity of DNA science. Lawyers try to break down DNA test results and make jurors
question the accuracy of the evidence. This was evident in the O.J. Simpson trial.
Simpson was accused of the murders of his wife Nicole Simpson and Ron Goldman, a
friend of Nicole. Simpson’s lawyers put doubt in the juror’s minds through racism, bad
evidence handling, and a possibility of Simpson being framed. Even though DNA testing
proved that Simpson was guilty, he was acquitted of all charges. This shows that DNA
evidence in everyone’s eyes is not valid without substantial evidence.
I feel that DNA evidence is a good way to aid in criminal investigations
but is not good stand-alone evidence at this time. This is because the people that make up
juries do not fully understand the accuracy of DNA testing, therefore creating a loop-hole
as we saw in O.J. Simpson’s trial. Furthermore all aspects of DNA evidence used in
courts today would be sufficient in convictions if the understanding of DNA analysis was
understood by everyone.