Dna fingerprinting presentation

2. CONTENTS
 Introduction to DNA.
 What is DNA fingerprinting?
 Sources of DNA .
 Steps in DNA Fingerprinting.
 Uses of DNA Fingerprinting.
 Famous cases.

4. WHAT IS DNA FINGERPRINTING?
 DNA Fingerprinting is a forensic
technique used to identify
individuals by characteristics of
their DNA.
 This technique is based on the
nucleotide sequence of a DNA
molecule.
 The process of DNA Fingerprinting
was invented by Alec Jeffrey at the
university of Leicester in 1985.
 Every person show an unusual
sequence of 20-100 base pairs which
are repeated several times, they are
termed as variable number of
tandem repeats(VNTR).
 The length of the regions having
VNTRs are different in every
individual, this unique detectable
pattern is the key factor in DNA
profiling.
EXTRACTION is the process in which
the DNA are release from the cell.
Amplification is the process of
producing multiple copies of the DNA.
Separation is the process of separating
amplified DNA product to permit
subsequent identification.
Analysis & Interpretation is the process of
quantitatively and qualitatively comparing
DNA evidence samples to known DNA
profiles.
Quantitation is the process of
determining how much DNA you have

5. BONE
TEETH
BLOOD
HAIR
SALIVA
SEMEN
VISCERA
FINGERNAIL
SCRAPPING
VAGINAL
SWABS
SOURCES
OF DNA
BIOLOGICAL SAMPLES IN DNA
FINGERPRINTING:

6. STEPS IN DNA FINGERPRINTING
1) DNA Isolation
• Various material available like blood,semen,hair roots,tissue,teeth,bones,saliva
samples etc. is treated with chemicals /enzymes to extract DNA, which then
separated & purified.
3) DNA Cutting
• The DNA is cut into fragments using restriction
enzymes.
• Each restriction enzymes cuts DNA at a specific
base sequence.
• This is called as Restriction Fragment Length
polymorphism (RFLP).
2)DNAAmplification
• If the DNA quantity is small it is subjected to in vitro replication by a
technique called PCR to obtain more copies of DNA .

7. 4) Electrophoresis: Electrophoretic separation of different fragments.
• Fragments are separated on the basis of
size using a process called gel
electrophoresis.
• DNA fragments are injected into the wells
and an electric current is applied along the
gel.
• DNA is negatively charged so it is
attracted to the positive end of the gel.
• The shorter DNA fragments move faster
than the longer fragments.
• DNA is separated on basis of size.
5) Transfer DNA on nylon /nitrocellulose
membrane
• Bands are transferred o the nylon
membrane. The single stranded
DNA get embedded into nylon
membrane.

8. 6) HYBRIDIZATION
• Adding radioactive or colored probes to the
nylon sheet which is complementary to target
sequences.
• Each probe sticks to one or two specific places
on the sheet.
7) AUTORADIOGRAPHY
• The DNA bands due to radioactive probe give
photographic image on X ray film.
• It shows multiple number of bands that look
like bar codes and known as DNA fingerprints.
8) INTERPRETATION OF BAND PATTERNS
 Analysis of band patterns of different individuals
 Comparison of position of bands
 Computer software are also available for the analysis of DNA fingerprinting

9. APPLICATION OF DNA FINGERPRINTING
1) Paternity Test
 A child inherits 1 set of genes from mother
and 1 set from father.
 ½ of the bands in a pattern are from mother
and the other from father.
 Mitochondrial DNA mt.DNA is a
maternally inherited genetic material.
Nuclear DNA when not in sufficient amount
, mtDNA is used for forensic.
2) Diagnosis of inherited Disorders
 Helps diagnose disorders in both prenatal and new born
babies
 Disorders may include cystic
fibrosis,hemophilia,Hungtington’s diseases,familiar
Alzheimer’s, sickle cell anemia,thalassemia,and much more.

10. 3. Crime Investigation
 Especially in murder or man-slaughter, sexual offences,assaults,robbery,house-
breaking,burglary,kidnapping,etc.
4. Solving medical problems
 DNA profiles can be used to determine whether a particular person is the
parent of a child.
 A child’s paternity (father) and maternity (mother) can be determined.
 This information can be used in the cases of paternity suits, inheritance cases,
immigration cases.
5. Wildlife crime :-
 Solving the cases of poaching, inbreeding, cure of genetics diseases, etc.
6. Natural & Man made disasters
 Identification of mass casualties during earthquakes, floods, air crashes, train
accidents, explosions, fire, specially identification of the mutilated bodies in
such incidences.

11. FAMOUS CASES SOLVED USING DNA FINGERPRINTING
 In 2002, Elizabeth Hurley used DNA
fingerprinting to prove that Steve Bing was the
father of her child Damien.
 Colin Pitchfork was the first criminal caught
based on DNA fingerprinting evidence.
 He was arrested in 1986 for the rape and
murder of two girls and was sentenced in 1988.

12. THANK YOU