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HUMAN DNA TYPING

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Title: Slide 1 Author: Niaz Ali Last modified by: Haroon Mastaan Created Date: 7/6/2010 3:30:42 AM Document presentation format: On-screen Show (4:3) – PowerPoint PPT presentation

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Title: HUMAN DNA TYPING


1
HUMAN DNA TYPING
  • Akhtar Hussain
  • Asstt . Prof.
  • COBAM
  • UOP

2
  • What
  • Why
  • How
  • Where
  • When

3
  • Finger Prints
  • DNA Finger Prints

4
DNA Fingerprinting What is it?
  • Series of techniques used to differentiate one
    subjects DNA from another
  • Compares hypervariable regions, or variable
    numbers of tandem repeats (VNTRs) or STRs
  • Synonyms are DNA profiling, DNA typing, DNA
    fingerprinting

5
  • The basic structure of everyones DNA is the same
  • the difference between people is the ordering of
    the base pairs
  • AGTC ATCG
  • Every person can be distinguished by the sequence
    of their base pairs
  • Even though two unrelated humans differ in their
    DNA only by 0.1 to 0.2 there are still up to 6
    million base pair differences
  • It is these differences that are used to create a
    unique DNA fingerprint also known as DNA
    profile

6
  • APPLICATIONS
  • Paternity suites
  • Victim identification
  • Identifying suspects

7
Who and when?
  • Sir Alec Jeffreys 1985
  • Hypervariable regions in the DNA
  • Published two key papers about the VNTRs
  • Jeffreys AJ, Wilson V, Thein SL (1985)
    Individual-specific fingerprints of human DNA.
    Nature 316(4)76-79.
  • Gill P, Jeffreys AJ, Werrett DJ (1985) Forensic
    application of DNA fingerprints. Nature
    318(6046)577-579.

8
Preparation of a DNA Fingerprint Steps
  • Specimen collection at crime scene
  • DNA Extraction
  • Blood Samples from suspects
  • PCR
  • Gel Electrophoresis
  • Allele Scoring
  • Results
  • ????????

9
How do crime scene investigators create a DNA
profile?
Sample Obtained from Crime Scene or Paternity
Investigation
Biology
DNA Extraction
Technology
Separation and Detection of PCR Products (STR
Alleles)
Genetics
Comparison of Sample Genotype to Other Sample
Results
10
PCR amplification of DNA
STR locus
Design primers that anneal to STR locus Amplify
all the regions of the chromosome where the STRs
exist.
STR locus
11
PCR allows you to make millions of copies of the
STR region from a single copy of DNA you
recovered from crime scene.
12
Different STRs at other loci
STR1 STR2 STR3
Do any of the individuals compare with forensic
sample?
13
Analysis used 3 different VNTR loci for each
suspect giving 6 bands
14
DNA Sources
Saliva Urine semen Bones Blood Teeth T
issues vaginal secretions Mucus Nails why
saliva tear urine etc Hair Tear
15
VNTR Vs STR
  • STRs are used when DNA is scarce
  • DNA Index System (DIS)
  • - 13 STRs Loci
  • WHY STRs ?

16
http//www.cstl.nist.gov/div831/strbase/images/cod
is.jpg
17
Uses of CODIS Profiles
  • Forensic cases
  • Paternity testing
  • Missing persons investigations
  • Military DNA dog tag
  • Convicted felon DNA databases
  • Story of California

18
How much and older DNA ?
  • Lucard Principal
  • Cigarettes
  • Bottles
  • Touch of Finger
  • Spit
  • Hair Follicle
  • Tissue paper etc
  • 1000 years old

19
Famous cases
  • In 2002 Elizabeth Hurley used DNA profiling to
    prove that Steve Bing was the father
  • of her child Damien

20
Famous Cases
  • 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.

21
Famous Cases
  • O.J. Simpson was cleared of a double murder
    charge in 1994 which relied heavily on DNA
    evidence.
  • This case highlighted lab difficulties.

22
Zimbabwe Immigration Case
  • Mothers and 3 children case Vs Home Office
  • If you like you may ask me about male nurse of
    Birmingham
  • The case was not immigration

23
1st Trial in US November 3, 1987
  • Trial held in Orlando, Florida
  • It was testified that semen left on the victim
    matched Andrews DNA

24
New York v Castro
  • Jose Castro, Vilma Ponce and Natasha.
  • Confessed pled guilty of murder

25
Nevada
  • Police Sherriff and Hooker

26
Pakistan
  • Sultan Rahi
  • Javed Iqbal 1999/2000
  • Lady Griffith School Peshawar 1996
  • Holy Family Hospital 2001
  • War on Terror

27
  • Paternity tests at hospitals
  • Maternity Centres

28
Advantages
  • High Resolution Power
  • DNA profile cant be altered by suspect
  • DNA remains intact under many harsh conditions
  • May be able to obtain information about an
    individual from a relatives DNA

29
Disadvantages
  • Human error either at the crime scene, the
    laboratory, or the police station
  • Ethical issues pertaining to identification of
    genetic defects or medical conditions
  • Monozygotic twins

30
  • JAZAK ALLAH
  • Allah is RAHEEM , KAREEM, MUJEEB, WADOOD and
    HASEEB
  • Astaghfar
  • Drood Sharif
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