Forensic science is the use of scientific knowledge in legal situations.
The DNA profile of each individual is highly specific.
The chances of two people having exactly the same DNA profile is 30,000 million to 1 (except for identical twins).
Biological materials used for DNA profiling
Body tissue cells
DNA samples have been obtained from vaginal cells transferred to the outside of a condom during sexual intercourse.
The pattern of the DNA profile is then compared with those of the victim and the suspect.
If the profile matches the suspect it provides strong evidence that the suspect was present at the crime scene (NB:it does not prove they committed the crime).
If the profile doesn’t match the suspect then that suspect may be eliminated from the enquiry.
A violent murder occurred.
The forensics team retrieved a blood sample from the crime scene.
They prepared DNA profiles of the blood sample, the victim and a suspect as follows:
Blood sample from crime scene
DNA profiles can be used to determine whether a particular person is the parent of a child.
A childs paternity (father) and maternity(mother) can be determined.
This information can be used in
Example: A Paternity Test
By comparing the DNA profile of a
mother and her child it is possible to
identify DNA fragments in the child
which are absent from the mother and
must therefore have been inherited
from the biological father.
Is this man the father of the child?
In 2002 Elizabeth Hurley used DNA profiling to prove that Steve Bing was the father
of her child Damien
Colin Pitchfork was the first criminal caught based on DNA fingerprinting evidence.
He was arrested in 1986 for the rape and murder of two girls and was sentenced in 1988.