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HUMAN DNA TYPING

HUMAN DNA TYPING. Akhtar Hussain Asstt . Prof. COBAM UOP. What Why How Where When. Finger Prints DNA Finger Prints. DNA Fingerprinting What is it ?. Series of techniques used to differentiate one subject’s DNA from another

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HUMAN DNA TYPING

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

  2. What • Why • How • Where • When

  3. Finger Prints • DNA Finger Prints

  4. DNA FingerprintingWhat is it? • Series of techniques used to differentiate one subject’s 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 everyone’s 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 FingerprintSteps Specimen collection at crime scene • DNA Extraction • Blood Samples from suspects • PCR • Gel Electrophoresis • Allele Scoring • Results • ????????

  9. DNA Quantitation PCR Amplification of multiple (STR) markers Sample Genotype Determination Case Report If match occurs, comparison of DNA profile to population databases 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. 1 strand of DNA Heat to denature double- stranded DNA 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 atother 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 Tissues 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/codis.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 USNovember 3, 1987 • Trial held in Orlando, Florida • It was testified that semen left on the victim matched Andrew’s 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 can’t be altered by suspect • DNA remains intact under many harsh conditions • May be able to obtain information about an individual from a relative’s 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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