DNA fingerprinting is a technique developed in 1985 by Alec Jeffreys that analyzes variations in repeated sequences of DNA to generate unique profiles for identification purposes. It involves extracting DNA from samples, cutting the DNA into fragments using restriction enzymes, separating the fragments via gel electrophoresis, and comparing banding patterns to determine if two DNA samples match. DNA fingerprinting is widely used for criminal investigations, paternity testing, and tracing the origin of food and other products.

1. DNA Fingerprinting
Each DNA profile is Unique
Alec Jeffreys, 1985

2. Contents
Some basic facts
Introduction
History of DNA fingerprinting
Stages of DNA fingerprinting
Methods of DNA fingerprinting
Applications
•Crime
•Food
•Miscellaneous

3. Some baSic factS
.
When the
number is On DNA sequence of
not known, nucleotide
variable, or
Is repeated again
irrelevant, it
is sometimes and again but differ
called for person to person
a variable
number When between 10 and 60 nucleotides are
tandem repeated – Mini- satellite
repeats
(VNTR) Those with fewer are known as
microsatellites or short tandem repeat

4. introduction
It is
the number of
times
that these
STRs are
repeated that
produces
Regions of chromosomes that code for
Extrons contain blocks of repeated
the variations
proteins are called introns.
nucleotides short tandem repeats
in (STRs)
individuals. Other regions that are non-coding are called
extrons.

5. introduction
.
DNA fingerprinting on
the basis of STR doesn’t
give an Individual
DNA fingerprint but able to
fingerprint determine the two
ing samples are form the
Is also same person
called "DNA fingerprinting" is a technique that
DNA allows us to see differences in DNA
profiling fragments from one person to another
in more general form.

6. HiStory of dna
fingerprinting
•Up to 1984, the only method of
establishing and authenticating
personal identification was by the
fingerprint process.
•DNA fingerprinting technique was
devised in 1985 by Alec Jeffrey at
University of Leicester in England,
while working on the sequences
within myoglobin gene.

7. Stages of DNA Fingeprinting
DNA is extracted from sample
•Each cell is surrounded by
cell membrane
•DNA is enclosed within the
nucleus

8. Stages of DNA Fingeprinting
DNA is extracted from sample
To extract DNA , most commonly used detergent is Sodium
Dodecyl Sulfate (SDS).
Digestio
n of
proteins
and
lipids
around
the cell

9. Stages of DNA Fingerprinting
DNA is extracted from sample
•DNA in the
nucleus of the cell is
molded, folded, and
protected by Proteins
•Proteinase K is
used to break up the
proteins

10. Stages of DNA Fingerprinting
Ethanol Precipitation
The DNA must be purified from the cell extract.
Ethanol lowers the effective water concentration, causing
large bio-molecules to interpenetrate and aggregate. The result
is a visible precipitate at the interface, where the ethanol is
concentrated.
 DNA will rise into the alcohol layer from the cell extract
layer.
 The protein and grease parts dissolve in the bottom, watery
layer

11. Stages of DNA Fingerprinting
DNA cuts with the help of Restriction
Endonuclease
DNA is cut into millions of small fragments with the help of
restriction endonucleases
Restriction enzymes chop DNA at specific sequences.
the patterns occur in different places in different individual , the
length of the fragment differs from person to person.
e.g The EcoRI restriction enzyme recognizes the following sequence
-C-A-A-T-T-G-
-G-T-T-A-A-C

12. Stages of DNA Fingerprinting
Separation of DNA fragments
•DNA fragments are separated
by electrophoresis
•DNA is negatively charged
so it is attracted to the positive
end of the gel.
Separated DNA on the basis of gel
electrophoresis

13. Stages of DNA Fingerprinting
Southern blotting
•Patterns of fragments
are transferred to a nylon
membrane by a process called
Southern blotting.

14. Stages of DNA Fingerprinting
DNA fingerprints compared
nylon or nitrocellulose (From
southern blot) sheet is placed under
X-ray film
The radioactive probes on the
DNA fragments expose the film
produces visible pattern of light
and dark bands which is unique to
each individual
Light and dark bands of DNA when nylon
film exposed to X- ray

15. Methods of DNA Fingerprinting
Restriction enzyme based
fingerprinting
•Relatively straight forward
•When genomic DNA is cleaved with particular restriction enzymes, the
resulting fragments can contain a minisatellite (VNTR) region
•gel electrophoresis separates the digested DNA into bands based on the
length of the fragments, the pattern of bands reflects the number of
repeats in a minisatellite
•each person’s DNA will yield a unique banding pattern

16. Methods of DNA Fingerprinting
PCR – based DNA fingerprinting
• By virtue of the amplification process, it is possible to begin with only
a tiny amount of DNA
• possible to fingerprint the DNA of a single cell
• Also possible to analyze old or degraded samples using PCR-based
fingerprinting
• Degraded DNA - be nearly impossible to fingerprint with restriction
analysis

17. Methods of DNA Fingerprinting
Amplified fragment Length
Polymorphism
Come in 90’s
remains attractive because of its relatively less complicated operation
and the cost-effectiveness
use of gel in its analysis phase, there are issues of bunching of the
VTRN's, causing misidentifications in the process.

18. Methods of DNA Fingerprinting
STR ( Short tandem repeats)
Mostly widely used method for comparing samples of persons
STR analyzes how many times base pairs repeat themselves on a
particular location on a strand of DNA
Has been extremely successful for use in the personal identification of
criminal suspects, paternity issues, as well as in identification of the
diseases.

19. Applications of DNA fingerprinting
Mostly used to solve crime and medical, paternity problems
•Violent murder occurred
•Rape cases
• Inheritance cases
•Immigration cases
•DNA fingerprinting also found recent applications in food
industry
•Recent application in breast cancer detection

20. Applications of DNA Fingerprinting
Crime scene
• Pattern of the
DNA profile is
compared with those
of the victim and the
suspect
• profile matches the
suspect - provides
strong evidence that
the suspect was
present at crime scene

21. Applications of DNA fingerprinting
Application in
Food
Product identification
Genetic diversity analyses
Traceability testing

22. Applications of DNA fingerprinting
Product identification.
Based on found genetic similarities or differences, a
product's identity can be established.
makes it possible to distinguish raw materials or
products from different suppliers
High-value products, such as Basmati rice and
Arabica coffee that cannot always be easily and
reliably distinguished from inferior varieties.

23. Applications of DNA fingerprinting
Genetic diversity analysis
DNA fingerprints - been applied in the genetic diversity
analysis of wine cultivars
some varieties consisted of more than one genetically distinct
variety, and that varieties that had been considered distinct were
genetically identical
Such an analysis is interesting for many crops and forms the
basis for the analysis of variations in product quality.

24. Applications of DNA fingerprinting
Traceability testing
DNA fingerprinting technology can be used for traceability
testing
comparison of a fingerprint of a cow's ear and the fingerprint
of meat products will show whether the two samples originate
from the same animal

25. Applications of DNA fingerprinting
Commercial sauerkraut
fermentations
 Process available generates more salt as waste – disposable
problem
To avoid this, one has to study bacterial ecology – previous it
was studied by bio- chemical methods
But , DNA fingerprinting found application – shows more
complex behavior of bacterial viruses which produces waste

26. Applications of DNA fingerprinting
Commercial sauerkraut
fermentations
 so , on the basis of these data, one can generate new
fermentation technology – which produces less salt waste and
increases the yield

27. Applications of DNA fingerprinting
Wines – use of GM yeast
and GM grapes
 Scientists at the Bavarian State Institute for Viticulture
and Horticulture in Würzburg, Germany, use DNA
fingerprinting to analyze wines.
Genetically modified (GM) yeast and GM vines are
undergoing field trials

28. Applications of DNA fingerprinting
False labeling issue
 Wang Jun and his group at the Chinese University of Hong
Kong used DNA fingerprinting to differentiate between Panax
ginseng (ginseng) and Panax quinquefolius (American ginseng)
price of P. quinquefolius is usually 5–10 times greater than
that of cultivated Panax ginseng

29. Applications of DNA fingerprinting
Accessions ( distinct varieties) of
plants
 accessions are traditionally classified on the basis of
morphology, but it is suspected that numerous duplicates are
present
problem is increased by the fact that the same accessions are
often named differently in different countries

30. Applications of DNA fingerprinting
Accessions ( distinct varieties) of
plants
 twenty-one accessions of sweet potato from the South
African genebank were compared.
RAPD and SSR techniques were used
Results show that 4 accessions which are differently named
are the genetically same – DNA fingerprinting one can use to
identify and make gene banks of world more appropriate

31. Applications of DNA fingerprinting
Lactic acid bacteria
 DNA fingerprints of lactic acid bacteria were generated by
PCR
method made it possible to identify 37 isolates from raw milk,
industrial starters and yogurt
Differentiation at species, subspecies and strain level was
possible for
Lactobacillusdelbrueckii subsp. lactis, Lb.delbrueckii subsp bul
garicus and Str.thermophilus

32. Applications of DNA fingerprinting
Miscellaneous
• Fingerprinting has provided them to determine whether a
woman who had breast cancer at about as low as 10 cancer
cells
In evolutionary studies, DNA fingerprinting has even
traced the origin of all of mankind to Africa
•fingerprinting can also be used to trace plants and plant
products back to their sources

33. concluSion
.
One can use DNA fingerprinting is
DNA very useful technique to
fingerprinting solve many problems
related to crime, rape
In near era of and murder cases when
food science to very few evidences are
widen and available
know more •DNA samples must be prepared carefully
about the
products •Also , STR based method of DNA
fingerprinting is very easy and less time
consuming