VELAMMAL VIDYALAYA

ANUPANADI
MADURAI-625009

BIOLOGY PROJECT

SUBMITTED BY: T.VIRSHIN

INDEX
 INTRODUCTION
• A DNA sample taken from a crime
scene is compared with a DNA sample
a suspect.
•DNA fingerprinting was invented in
1984 by Professor Sir •DNA
fingerprinting is a laboratory
technique used to establish a link
between biological evidence and
suspect in a criminal investigation.

Alec Jeffreys.

•DNA fingerprinting involves the

identification of differences in
repetitive DNA. Repetitive DNA is a
specific region in DNA in which a
small stretch of DNA is repeated
many times.
•Through density gradient
centrifugations these repetitive DNA
are separated from the bulk genomic
centrifugation and the other small
peaks are known as satellite DNA.

•These sequence do not code for any

proteins normally but they constitute
a large portion of humans
genome.The satellite DNA is
classified into many categories such
as a microsatellites, nanosatellites
etc, on the basis of length of segment,
number of respective units, the base
composition (A:T rich or G:C rich),etc

•The satellite DNA sequences also

shows high degree of polymorphism
and forms,the basis of DNA
fingerprinting.

POLYMORPHISM

It is the variation in individuals at

genetic level. Polymorphism arises
due to mutations. It plays an
 important role in evolution and
speciation. In a population, if an
inheritable mutation is observed at
high frequency, it is referred to as
DNA polymorphism. There are
different types of polymorphism,
from single nucleotide change to
large scale changes.

In an individual, DNA from every tissue(e.g.

blood,hairfollicle,skin,bone,saliva etc)
showssame degree of polymorphism Thus,
they become very essentialidentification
tool in forensicapplications. As
polymorphism are inherited from parents to
children.
So, it is useful in paternity testing.
TECHNIQUE OF DNA FINGERPRINTING

Alec Jeffreys initially developed DNA

fingerprinting, also known as DNA
typing or DNA profiling, to find out
markers for inherited diseases. He
used a satellite DNA as a probe that
shows very high degree of
polymorphism and called it Variable
Number of Tandem Repeats(VNTRS).
The technique involved South
radiolabelled ern blot
 hybridisation using VNTR as a
probe.

PROCESS OF DNA FINGERPRINTING

SOUTHERN BLOT
Restriction digested genomic DNA
Stage 1: Sample Collection
DNA can be acquired from any bodily sample or liquid.
Buccal smear. salivation, blood, amniotic liquid, chorionic
villi, skin, hair, body liquid, and different tissues are
significant kinds of samples utilized.

Stage 2: DNA Extraction

We need to initially get DNA. To play out any Genetic
applications, DNA extraction is one Of the most
significant advances. Great quality and amount Of
DNA expands the conceivable outcomes of getting
better outcomes. You can utilize DNA extraction
enrolled beneath,
1. Phenol-chloroform DNA extraction strategy
2.CTAB DNA extraction strategy
3 -Proteinase K DNA extraction strategy
In any case, we emphatically prescribe utilizing a ready
to go DNA extraction unit for DNA fingerprinting-The
immaculateness and amount Of DNA ought to be —1.80
and IOOng, individually to play out the DNA test. Filter
the DNA utilizing the DNA sanitization unit, if necessary
.From that point onward, measure the DNA Utilizing the
UV-Visible spectrophotometer. Furthermore, perform
one Of the accompanying strategies recorded
underneath.
Stage 3: Restriction Absorption, Enhancement or
DNA Sequencing
Three regular strategies are utilized:
1 .RFLP based STR investigation
2.PCR based investigation
3. Real-time PCR investigation

Stage 4: Analysis of Results

As we examined, utilizing the southern blotting,
Agarose gel electrophoresis, narrow electrophoresis,
ongoing intensification, and DNA sequencing, the outcomes
for different DNA profiling can be gotten in which rt-PCR
and sequencing are much of the use in forensic science.

Stage 5: Interpreting Results

By looking at DNA profiles Of different examples,
varieties and likenesses between people can be
distinguished. Outstandingly , the whole procedure is
presently nearly automatic. We don't need to do
anything, the computer gives us conclusive outcome
 SCHEMATIC REPRESENTATION OF
DNA FINGERPRINTING

Few representative chromosomes has been

shown to contain different copy number of
VNTR. For the sake of understanding different
colour schemes have been used to trace the
origin each band in the gel. The two
alleles(patemal and maternal) of a
chromosome also contain different copy Of
VNTR It is clear that the banding pattem of
DNA from crime scene matches with
individual B not with A
APPLICATIONS OF DNA FINGERPRINTING

•DNA analysis in forensic tests

•Can be used to establish paternity
tests
•In criminal investigations
•To determine the frequency of
specific genes in a population which
gives rise to diversity
•Can be used to trace the role of genetic
drift in evolution
Personal identification

ADVANTAGES AND DISADVANTAGES

ADVANTAGES
1.1 t is an easy and painless method for the
subject being tested, It is less invasive then
taking a blood sample.
2. It is an affordable and reliable technique.

3. It can be conducted in a relatively short

amount of time.

4. Anyone at any age can be tested with

this method without any major concerns,

5. There is a large variety of uses such as in

legal claims, missing persons cases,
identification for the military, and paternity
and prenatal testing.

DISADVANTAGES
1. The sample of DNA can easily be
ruined during the process of DNA
fingerprinting, causing the sample to
become completely useless for testing
2. The process itself is complex and tedious,
and can give results that may be hard to
interpret

3. The test needs to be run on multiple

samples, a numerous amount of times for
ideal accuracy, Commonly, labs run each
test twice with four samples.

4. Privacy issues could occur if the

information isn't kept secure at the lab,
Personal information legally can only be
released with a written order' This
personal information if leaked, could
potentially complicate insurance processes,
health care and job prospects for an
individual
ECONOMIC VALUE
Develop cures- DNA Fingerprinting can be
used to develop cures, by studying the DNA
fingerprints of relatives who have the same
disorder; or comparing groups of people,
DNA patterns of the disease can be detected,
This is the first step to developing cures for
harmful diseases.
Evidence in crime- DNA Fingerpnnting is
used by the FBI and the police to solve
crimes at the Molecular level. Since 1987,
more than 150 cases have been solved with
the help of DNA Fingerprinting,
Diagnose inherited diseases-DNA
Fingerprinting can be used to detect early
diseases in order to prepare treatment
against the disease,
Personal identification- Every cell in one
human contains the exact same DNA
fingerprint, now that technology has
become advanced people have started to
collect samples to identify missing people or
casualties.
Fingerprinting has many practical uses and
is extremely beneficial to our society. It can
be used for learning and preventing
diseases, it plays a big role in Genetics, it
helps for knowing a person's identity, and it
can be used as evidence in criminal cases.
 FAMOUS CASES OF DNA
FINGERPRINTING

•Colin Pitchfork was the first criminal based on

DNA fingerprinting evidence-He was arrested
in 1986 for the rape and murder of the two
girls and was sentenced in 1988.

•Simpson was cleared of a double murder

charge in 1994 which relied heavily on DNA
evidence. This cases highlighted lab
difficulties.
 USES OF DNA FINGERPRINTING
Since it was invented in 1984, DNA
fingerprinting most often has been used in
court cases and legal matters. It can:
•Physically connect a piece of evidence to
a person or tule out someone as a
suspect. •Show who your parents,
siblings, and other relatives may be.
• Identify a dead body that's too old or
damaged to be recognizable,
DNA fingerprinting is extremely accurate,
Most Countries now keep DNA records on
file in much the same way police keep
copies of actual fingerprints.

IT ALSO HAS MEDICAL USES. IT CAN:

•Match tissues of organ donors with those
of people who need transplants.
•Identify diseases that are passed down
through your family.
•Help find cures for those diseases, called
hereditary conditions,

CONCLUSION
It was an amazing experience doing this
project, I gained a lot of information about
DNA Fingerprinting, It helped me to clear
many of my doubts. It is a really
interesting topic. In today's world DNA
fingerprinting is playing a very important
role,

Use of DNA fingerprinting has nowadays

increased as DNA analysis is a key to
linking suspects to biological evidence
and to identifying individuals in crimes
and disasters. Another important use is
the establishment of paternity in custody
and child support litigation.
 BIBLIOGRAPHY.
1.NCERT-BIOLOGY BOOK

2.ARIHANT-ALL IN ONE BOOK

3.IMAGES AND OTHER DATA FROM INTERNET

THANK YOU