DNA FingerPrinting and its Application

1. PRESENTATION:
Group 6
TOPIC:
DNA FingerPrinting
SUBJECT:
Genetic Engineering
DEPARTMENT:
Biochemistry
BILAL IRSHAD

2.  DNA fingerprinting is Laboratory Technique to
the analysis of DNA to identify individuals,
 DNA profiling
 DNA profiling is Laboratory Technique to the
analysis of individuals' DNA characteristics for
forensic studies

3. HISTORY
 1985: United Kingdom
 The process of DNA fingerprinting was invented by-
 Sir Alec Jeffreys
 Dr. peter Gill
 Dr. Dave Werrett at the University of Leicester in 1985.

4.  Chemical Structure of DNA is always the same.
 The order of the base pairs is different!
 3 Billion Nucleotides form our 46 chromosomes.
 In fact, no two people on Earth have exactly the
same genetic sequence, except identical twins.
 Every cell contains a copy of our DNA!

5. DNA Fingerprinting using VNTR,s
 VNTR(variable number of tandem repeats)- recognition that
variable numbers of repeated nucleotides can be found in DNA
and can be used for identification of individuals.
 VNTR’s provide a scientific marker for identity.
 Cut out the segment of the chromosome containing this variable number
of tandem repeats (VNTR's ).
 Identify the VNTR's for the DNA sequence of the repeat.

6.  DNA must be recovered from the cells or tissues of the
body.
 Blood
 Hair
 Saliva
 Semen
 Only a small amount of tissue is needed. For example, the
amount of DNA found in one drop of blood or in one hair
root is enough.
 Sample also taken from clothes, linen. or Comb etc.

7. Step 1:
 Cells are broken down to release
DNA.
 If only a small amount of DNA is
available it can be amplified
using the polymerase chain
reaction (PCR).

8.  More accurate than PCR
 Requires a large sample of fresh DNA
 Takes longer time & costly than PCR
 When a match if found, there is no question as to whether the
suspect was at the scene.
PCR – Polymerase Chain Reaction
 Takes less time, less costly
 Requires only a small sample
 That sample is amplified using polymerases to force the small
amounts of DNA to copy themselves many times.
 Can be performed on older samples If no match is found, the
donor was not at the scenes

9. Special restriction enzymes
are used to cut the DNA at
specific places.
The DNA pieces are sorted
according to size by a
technique called
electrophoresis.
 The DNA pieces are passed
through a gel made from
seaweed agarose.

10. Electrophoresis
DNA fragments are injected
into 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.

11. The DNA pieces are transferred to
a nylon sheet by placing the sheet
on the gel and soaking
them overnight.
The pattern of fragments are
transferred to a nylon membrane
by a process called Southern
blotting.

12. Adding radioactive or
colored probes to the nylon sheet
produces a pattern called the
DNA fingerprint. Each probe
typically sticks in only one or two
specific places on the nylon
sheet.

13. The final DNA fingerprint is
built by using several probes (5-
10 or more) simultaneously. It
resembles the bar codes used by
grocery store scanners.
 Police use the fingerprints to
compare a suspect’s DNA to
the DNA found at a crime
scene.

15. Paternity Test
By comparing the DNA profile of a mother and
her child it is possible to identify DNA fragments
in the child which are absent from the mother
and must therefore have been inherited from
the biological father.

16.  1 Murderer
 2 Rapist
 3 Thieves

17.  Diagnosis of Disease& Gene mapping
 Diagnose inherited disorders in both prenatal and new born babies.
 These disorders may include
 Alzheimer's,(21) Alzheimer's disease is the most common type of dementia.
 (identification by RFLP&VNRT)
 Alzheimer's disease involves parts of the brain that control thought, memory,
 sickle cell anemia: (11) is one of a group of inherited disorder
 It affects the shape of red blood cells,
 Cystic Fibrosis:
 a genetic condition (7)
 Lung infection and problems with digesting food

18.  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.
 In 1994, Simpson was arrested and charged with the
murders of his ex-wife, Nicole Brown
 O.J. Simpson was cleared of a double murder charge
in 1994 which relied heavily on DNA evidence.
 In 1995 UK established the world frist National DNA
database for criminal investigation
 This case highlighted lab difficulties.
 In 2002 Elizabeth Hurley used DNA profiling to
prove that Steve Bing was the father of her child
Damien