PCR%20has%20numerous%20applications%20:

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PCR has numerous applications
1) Gene isolation
2) Mapping of complex traits
3) Molecular taxonomy
4) Forensic science ( DNA fingerprinting)
5) Isolating ancient DNA sequences
6) Diagnosis of inherited disease.
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Professor Sir Alec Jefferys of Leicester
University realised in 1983 that VNTR variation
due to the presence of different numbers of
microsatellite repeat sequences at the same
chromosomal location could be used to distinguish
between individuals in a population
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DNA fingerprinting
DNA fingerprinting is based on the fact that
large portions of the eucaryotic genome consists
of repetitive, non-coding sequences.
These repeat sequences are found all over the
genome, on each chromosome and consists of
repeats of the same sequence.
V ariable N umber T andem R epeats
VNTRs
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VNTRs are based on the existence of
microsatellite repeat sequences
These are repeats of small sequences e.g. CACA
These repeats are scattered throughout the genome
CACA CACA CACA CACA CACA CACA - Person A
CACA CACA CACA CACA Person B
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DNA fingerprinting is based on the fact that
individuals in a population have different
numbers of repetitive sequences at the SAME locus.
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The principle of DNA fingerprinting is VERY
SIMPLE
Use PCR primers which amplify across the variable
region
In different individuals, bands of different
sizes will be amplified from the genome
This leads to the fingerprint unique for every
individual.
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PCR in Forensic science
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Paternity profiling
Which child is least likely to be the biological
offspring of this couple?
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Rape Investigation
1. Known blood sample of victim 2. Known
blood sample from defendant 3. DNA size
markers 4. Female fraction from vaginal swab
of victim 5. Male fraction from vaginal
swab of victim.
Q is the suspect (2) guilty?