Dna fingerprinting

1. DNA DNA
FINGERPRINTINGFINGERPRINTING

2. DNADNA
Is a unique to every person but the Is a unique to every person but the
same for the cell to cell within the same for the cell to cell within the
same person.same person.
DNA cannot be altered*DNA cannot be altered*
–Actually DNA can be altered in the lab, but you can’t Actually DNA can be altered in the lab, but you can’t
change your own DNAchange your own DNA

3. Two kinds of fingerprintTwo kinds of fingerprint
Conventional fingerprintConventional fingerprint
DNA fingerprintDNA fingerprint
–Becoming the primary Becoming the primary
method for identifying method for identifying
and distinguishing and distinguishing
among individual human among individual human
beingbeing

4. What is DNA What is DNA
Fingerprinting?Fingerprinting?
A technique used by scientists to A technique used by scientists to
distinguish between individuals of the distinguish between individuals of the
same species using only samples of same species using only samples of
their DNA their DNA

5. Who Invented it?Who Invented it?
The process of DNA The process of DNA
fingerprinting was invented by fingerprinting was invented by
Alec Jeffreys at the University Alec Jeffreys at the University
of Leicester in 1985. of Leicester in 1985.
He was knighted in 1994.He was knighted in 1994.

6. DNA Fingerprinting Basics
Different individuals carry different alleles.
Most alleles useful for DNA fingerprinting differ on the basis of
the number of repetitive DNA sequences they contain.

7.  Crime scene Crime scene
 Human relatednessHuman relatedness
 PaternityPaternity
 Animal relatednessAnimal relatedness
 Anthropology studiesAnthropology studies
 Disease-causing organisms Disease-causing organisms
 Food identificationFood identification
 Human remainsHuman remains
 Monitoring transplantsMonitoring transplants
DNA Fingerprinting Real DNA Fingerprinting Real
WorldWorld
Applications Applications

8. CrimeCrime
Forensic science is the use of Forensic science is the use of
scientific knowledge in legal scientific knowledge in legal
situations.situations.
The DNA profile of each individual The DNA profile of each individual
is highly specific.is highly specific.
The chances of two people having The chances of two people having
exactlyexactly the same DNA profile is the same DNA profile is
30,000 million to 1 (except for 30,000 million to 1 (except for
identical twins). identical twins).

9. Biological materials used Biological materials used
for DNA profilingfor DNA profiling
BloodBlood
HairHair
SalivaSaliva
SemenSemen
Body tissue cellsBody tissue cells
DNA samples have DNA samples have
been obtained from been obtained from
vaginal cells vaginal cells
transferred to the transferred to the
outside of a condom outside of a condom
during sexual during sexual
intercourse.intercourse.

10. A DNA Fingerprint
A DNA fingerprint used in a
murder case.
The defendant stated that the
blood on his clothing was his.
What are we looking at? How
was it produced?
When many genes are
analyzed, each with many
different alleles, the chance
that two patterns match by
coincidence is vanishingly
small.

11. DNA Profiling can solve DNA Profiling can solve
crimescrimes
The pattern of the DNA profile is then The pattern of the DNA profile is then
compared with those of the victim and the compared with those of the victim and the
suspect.suspect.
If the profile If the profile matchesmatches the suspect it provides the suspect it provides
strong evidence that the suspect was strong evidence that the suspect was
present at the crime scene (present at the crime scene (NB:it does NB:it does
not prove they committed the crime).not prove they committed the crime).
If the profile If the profile doesn’tdoesn’t match the suspect then match the suspect then
that suspect may be eliminated from the that suspect may be eliminated from the
enquiry.enquiry.

12. ExampleExample
A violent murder occurred. A violent murder occurred.
The forensics team retrieved a blood The forensics team retrieved a blood
sample from the crime scene. sample from the crime scene.
They prepared DNA profiles of the They prepared DNA profiles of the
blood sample, the victim and a blood sample, the victim and a
suspect as follows:suspect as follows:

13. Was the suspect at the Was the suspect at the
crime scene?crime scene?
Suspects
Profile
Blood sample
from crime
scene
Victims
profile

14. Famous CasesFamous Cases
Colin Pitchfork was Colin Pitchfork was
the first criminal the first criminal
caught based on caught based on
DNA fingerprinting DNA fingerprinting
evidence. evidence.
He was arrested in He was arrested in
1986 for the rape 1986 for the rape
and murder of two and murder of two
girls and was girls and was
sentenced in 1988. sentenced in 1988.

15. AltantuyaaAltantuyaa
Malaysian police found fragments of bone, later Malaysian police found fragments of bone, later
verified as hers, in forested land near the Subang verified as hers, in forested land near the Subang
Dam in Puncak Alam, Shah Alam. Police investigation Dam in Puncak Alam, Shah Alam. Police investigation
of her remains revealed that she was shot twice of her remains revealed that she was shot twice
before C-4 explosives were used on her remains, before C-4 explosives were used on her remains,
although there has been later suggestion that the C-4 although there has been later suggestion that the C-4
explosives may have killed her. When her remains explosives may have killed her. When her remains
were found their identity could only be confirmed with were found their identity could only be confirmed with
DNA testing.DNA testing.

16. Solving Medical Solving Medical
ProblemsProblems
DNA profiles can be used to determine DNA profiles can be used to determine
whether a particular person is the parent of whether a particular person is the parent of
a child.a child.
A childs paternity (father) and A childs paternity (father) and
maternity(mother) can be determined.maternity(mother) can be determined.
This information can be used inThis information can be used in
•Paternity suitsPaternity suits
•Inheritance casesInheritance cases
•Immigration casesImmigration cases

17. Example: A Paternity Example: A Paternity
TestTest
By comparing the DNA profile of a By comparing the DNA profile of a
mother and her child it is possible tomother and her child it is possible to
identify DNA fragments in the child identify DNA fragments in the child
which are absent from the mother and which are absent from the mother and
must therefore have been inherited must therefore have been inherited
from the biological father.from the biological father.

18. Is this man the father of Is this man the father of
the child?the child?
Mother Child Man

19. In general the child’s In general the child’s
DNA must be a DNA must be a
combination of Mary’s combination of Mary’s
DNA and one of the DNA and one of the
men. Which man is the men. Which man is the
father?father?
Answer: Larry Answer: Larry
Paternity Test Paternity Test

20. DNA fingerprinting is used DNA fingerprinting is used
for identification. for identification.
DNA fingerprinting depends DNA fingerprinting depends
on the probability of a match.on the probability of a match.
–Many people have the same Many people have the same
number of repeats in a certainnumber of repeats in a certain
region of DNA.region of DNA.
–The probability that two people The probability that two people
share identical numbers of share identical numbers of
repeats in several locations isrepeats in several locations is
very small.very small.
(mother) (child 1) (child 2) (father)

21. Famous casesFamous cases
In 2002 Elizabeth In 2002 Elizabeth
Hurley used DNA Hurley used DNA
profiling to prove profiling to prove
that Steve Bing was that Steve Bing was
the father the father
of her child Damienof her child Damien

22. Food IdentificationFood Identification

23. The detection of pork in
processed food
L 1 2 3 4 5 6 7 8 9 10 11 12 13
14
BseD1 restriction profile of cyt b PCR products amplifiedfrom meat and food
samples. L: 100 bp DNA ladder; 1: chicken, 2: beef; 3: mutton; 4: pork;
5, 6, 7: beef burgers; 8, 9, 10: chicken burgers; 11, 12, 13: sausages; 14: pork cocktail

24. The End…..The End…..