DNA and Crime
Deoxyribonucleic Acid - the fingerprint of life also know as DNA was
first mapped out in the early 1950’s by British biophysicist, Francis Harry
Compton Crick and American biochemist James Dewey Watson. They determined the
three-dimensional structure of DNA, the substance that passes on the genetic
characteristics from one generation to the next. DNA is found in the
chromosomes in the nucleus of a cell.
"Every family line has it’s own unique pattern of restriction-enzyme DNA
fragments. This variation in patterns of DNA fragments found in human genetic
lineages is called ‘restriction-fragment length polymorphism’(RFLP)." (Louis
Levine, ?) Because each person, except for identical twins(which have the
exact same DNA), is formed from two family lines the pattern of sizes of the
fragments from an individual is unique and can serve as a DNA fingerprint of
that person. These ‘fingerprints’ have became very important in identifying
criminals in a number of violent crimes where the victims aren’t able to. Blood
or semen stains on clothing, sperm cells found in a vaginal swab taken after a
rape, or root hairs are all available for analysis. Although other body tissues
such as skin cells and saliva can provide genetic information about a person for
Forensic Science purposes, blood is the most useful source of inherited traits.
If the DNA fingerprints produced from two different samples match, the two
samples probably came from the same person.
Here are some examples of court cases where DNA plays an important roll
in the outcome of the trial.
Hauppauge N.Y.: After 11 years in prison for rape Kerry Kotler cried tears
of joy becoming one of the first convicts in the United States to be freed by
DNA technology. At a banquet held for Kotler he received a standing ovation from
the guest’s of his lawyer, Barry Schech and Peter Neufeld, who would later use
their DNA expertise to help free O.J. Simpson.
Now the very weapon used to free Kotler will be used against him and
instead of his lawyers praising DNA testing they will be trying to tear it down.
Four years after being released from prison Kotler was charged with another rape
and the DNA test matched him to the semen found on the victims clothing. Posing
as a police officer he forced a 20 year old college student off the highway and
raped her. A partial license plate number and a description of the car led them
to Kotler. The semen matched Kotler’s blood and the chances of the semen being
somebody else’s is one to 7.5 million. Also, dog hairs on the victims clothing
matched hairs from Kotler’s German shepherd. Kotler, 37, is free on $25000 bail
and could get up to 50 years in jail if convicted of rape and kidnapping.
Anamosa, Iowa: 22 year old Cathy Jo Bohlken was sexually assaulted and
murdered. Genetic evidence from fluid taken from her body points to an 18 year
old named Travis Jamieson....