DNA fingerprinting

1. DNA
FINGERPRINTING
AND
FOOTPRINTING
SHENIKHA AG

2. DNA FINGERPRINTING
• In finger printing , thump impression is taken on a paper
using ink or dye.
• In DNA fingerprinting ,images of DNA band are captured
on an X-ray film.
• Distinguishing the individuals according to their DNA
print pattern is called DNA fingerprinting
• Or DNA profiling or molecular fingerprinting
• Developed by Alec Jeffrey in 1984.

3. • Each person DNA fingerprint is unique and is more
significant than a fingerprinting
• DNA stores information in 4 letter code ,which constitute
blue print of each and every organism.
• DNA fingerprint of an individual is the description of a
specific alleles present at a series of polymorphic loci in
his or her genome.
• A polymorphic locus is that region of genomic DNA
whose sequence is different in different individuals.

4. • The polymorphism of mini satellite , micro satellite and mini
variant repeats is analysed for DNA fingerprinting. These
sequences together constitute the VNTR ( variable number
of tandem repeats.
• In minisatellite DNA the repeats units are of 15 to 60 bp
• In microsatellite are 1 to 13 which are also called short
tandem repeat (STRs)

5. • The specific site at which VNTR sequence
is present constitutes a VNTR locus. And
the different alleles of this consist of
diffnt no.of repeating unit.
• The different alleles of VNTR locus are
detected either as an RFLP or through
PCR.

6. • RFLP is detected by digesting the genomic
DNA with a restriction enzyme that
cleave the DNA outside the region of
VNTR repeats on both side.
• This generates the VNTR fragments of
different lengths depending on the number
of repeats .
• This fragment migrate to different positions
in electrophoretic gel.
• The location of the bands in detected by
using VNTR sequence as probe.

7. • Minisatellite in human genome has a
common core sequence of 10 to 15 bp
• Each individual minisatellite is able to
detect about 1000 different minisatelites on
southern blot.

8. • Microsatellite are now used as PCR based
marker
• The sequence of unique DNA located on both
side of repeat are determined and used to
constrct 2 PCR primer.
• The primer are used for amplification of mini or
micro satellite
• Amplified pdt be of different lengtha in
diffrenent individuals.

9. Application of DNA
fingerprinting
1. It is extremely useful in identification of
criminals
2. Useful in clear cut identification of victims
of crimes or accident
3. Used to infer if 2 or more individual are
member of same family .
4. Identification of sex of individual in case
of badly damaged body

10. DNA FOOTPRINTING
• Technique used to locate protein binding site
on DNA molecule.
• Foot printing work on basis that interaction
with regulatory protein protect the DNA
sequence from degradative action of
endonuclease such as Dnase 1