1. DNA PROFILING IS USED TO
IDENTIFY AN INDIVIDUAL
A process where we used to analysis
our DNA. For example; through
traces left by our fingerprints.

2. THE PROCEDURE
First,
The DNA to be identified is extracted from the
source (blood stain or any sample taken from the
subject).
The DNA is cut into small pieces using restriction
enzymes.
This is because the easiest place to detect the
unique nature of individual DNA is in regions
where short sequences of bases are repeated
variable number of times-short tandem repeats
(STRs)

3. Second,
Polymerase chain reaction (PCR) technique is
used to amplify these regions in the DNA by
making multiple copies.
It use:
i) sequence-specific primer to bind to the DNA
that has been separated into single strands.
ii) a heat-stable version of the enzyme DNA
polymerase to polymerized these sections.
Temperature : 70˚C
This process can add up to a thousand bases per
minute.

4. Third,
The DNA fragments are then separated
and detected using gel electrophoresis.
Due to its phosphate groups, DNA carries
a negative charge.
So, the fragments move towards the
positive terminal by a distance that
corresponds to their molecular
sizesshorter fragments move further
than longer fragments.
The nitrocellulose sheet used in the
electrophoresis is treated with radiation.
This produces an
Autoradiogram  showing the position
of the fragments as dark bands.

5. Applications of DNA Profiling
To identify victims.
In forensic cases, to identify the suspect.
To confirm biological relationships between
individuals.
To determine relationships between
populations in the study of evolution,
migration and ecology.