DNA is the information needed by a cell in order to reproduce an
identical offspring. In some crimes detectives have no evidence or fingerprints
to tell who had committed a crime. Now there is a way of finding who has
committed the crime by a method called DNA Typing. DNA Typing is finding
bacteria or blood on clothing or skin and amplifying the gene. This process was
pioneered in the 1980's by a Scientist named Alec Jeffreys.
If blood, sperm, or any other human cells are left at the scene of a
crime, the DNA in the cells can be analyzed and compared with some DNA taken
from the suspect's blood. If they match, this information and testimony of a
scientist can be used to convict a rapist or murderer.
In the O.J. Simpson case DNA Typing was used. There was blood found
on various areas at the crime scene. The investigators gathered the evidence,
and took it to the laboratory where it was analyzed. The jury determined that
the samples were contaminated because of the way they were handled.
DNA Typing is not perfect. There are many loop holes in it. An example
is the O.J. Simpson trial. During the process the DNA may be tampered with or
In most rape cases DNA Typing is used by taking semen off the body of
clothes then amplifying the genes. The machine that copies the DNA is called
the PCR. The DNA is then cut and placed the wells in trays. PCR copies the
small pieces of DNA. It is performed by a blotting process. This process has
21 different catogories.
Other tests include those for tracing genetic diseases within families,
finding the genes that cause genetic diseases. DNA Typing can also prove the
relationship with families.
DNA Typing is becoming more common than ever. This process is helping
to free convicted people of crimes they may not have committed by taking samples
of the prisoners DNA and comparing it with the evidence left at the crime scene.