Role of dna fingerprinting in crimes


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Role of dna fingerprinting in crimes

  1. 2. Name: Naeem Abbas <ul><li>Roll NO: 89 </li></ul><ul><li>Msc Morning </li></ul><ul><li>4 th Semester </li></ul><ul><li>Seminar Topic: </li></ul><ul><li>Role of DNA Fingerprinting in Crimes. </li></ul><ul><li>Research Supervisor: Dr Faiza Amir </li></ul>
  2. 3. Contents <ul><li>History. </li></ul><ul><li>Introduction. </li></ul><ul><li>Making DNA Fingerprinting. </li></ul><ul><li>Practical Application. </li></ul><ul><li>DNA Profiling. </li></ul><ul><li>Example. </li></ul>
  3. 4. DNA fingerprinting
  4. 5. Historical background <ul><li>DNA fingerprinting was developed in 1984 by Alec. J. Jeffrey at the University of Leicester </li></ul><ul><li>He was studying the gene of myoglobin. </li></ul>
  5. 6. DNA Fingerprinting <ul><li>The chemical structure of everyone's DNA is the same. </li></ul><ul><li>The only difference between people (or any animal) is the order of the base pairs </li></ul><ul><li>The information contained in DNAis determined primarily by the sequence of letters along the zipper . </li></ul>Structure of DNA
  6. 7. The different sequence Segments that vary in size and composition and have no apparent function are called minisatellites The different sequences is the same as the word &quot;POST&quot; has a different meaning from &quot;STOP&quot; or &quot;POTS,&quot; even though they use the same letters. i
  7. 8. <ul><li>Using these sequences, every person could be identified by the sequence of their base pairs </li></ul><ul><li>There are so many millions of base pairs, the task would be very time-consuming Instead, scientists are able to use a shorter method, because of repeating patterns in DNA. </li></ul><ul><li>These patterns do not, however, give an individual &quot;fingerprint,&quot; </li></ul><ul><li>They are able to determine whether two DNA samples are from the same person, related people, or non-related people. </li></ul>
  8. 9. DNA Fingerprinting using VNTR's <ul><li>On some human chromosomes, a short sequence of DNA has been repeated a number of times. </li></ul><ul><li>The repeat number may vary from one to thirty repeats these repeat regions are usually bounded by specific restriction enzyme sites cut out the segment of the chromosome containing this variable number of tandem repeats ( VNTR's ) </li></ul><ul><li>Identify the VNTR's for the DNA sequence of the repeat. </li></ul>
  9. 10. Making DNA Fingerprints <ul><li>DNA fingerprinting is a laboratory procedure that requires six steps: </li></ul><ul><li>1: Isolation of DNA. </li></ul><ul><li>2: Cutting, sizing, and sorting. </li></ul><ul><li>Special enzymes called restriction enzymes are used to cut the DNA at specific places </li></ul>
  10. 11. <ul><li>3: Transfer of DNA to nylon. The distribution of DNA pieces is transferred to a nylon sheet by placing the sheet on the gel and soaking them overnight. </li></ul><ul><li>4:Probing. Adding radioactive or colored probes to the nylon sheet produces a pattern called the DNA fingerprint. </li></ul>
  11. 12. <ul><li>5: DNA fingerprint. </li></ul><ul><li>The final DNA fingerprint is built by using several probes (5-10 or more) Continuously. </li></ul>
  12. 13. Practical Applications of DNA Fingerprinting <ul><li>1.Paternity and Maternity </li></ul><ul><li>Person inherits his or her VNTRs from his or her parents </li></ul><ul><li>Parent-child VNTR pattern analysis has been used to solve standard father-identification cases. </li></ul>
  13. 14. <ul><li>The primary method of assessing similarities is by use of DNA fingerprinting or DNA restriction analysis. </li></ul><ul><li>This process makes use of special proteins called restriction enzymes and sections of the chromosome called tandem repeats. </li></ul>
  14. 15. 2. Criminal Identification <ul><li>DNA isolated from blood, hair, skin cells, or other genetic evidence left at the scene of a crime can be compared </li></ul>3. Personal Identification <ul><li>The notion of using DNA fingerprints as a sort of genetic bar code to identify individuals has been discussed. </li></ul>
  15. 16. <ul><li>4.Diagnosis of Inherited Disorders </li></ul><ul><li>diagnose inherited disorders in both prenatal and newborn babies </li></ul><ul><li>These disorders may include cystic fibrosis, hemophilia, sickle cell anemia, thalassemia, and many others. </li></ul>
  16. 17. Tandem Repeats <ul><li>A region of the chromosome that contains multiple copies of a core DNA sequence that are arranged in a repeating fashion Repeats act as fillers or spacers between coded sections of DNA. </li></ul>
  17. 18. DNA Profiling <ul><li>A technique used by scientists to distinguish between individuals of the same species using only samples of their DNA </li></ul>
  18. 19. Stages of DNA Profiling <ul><li>Stage 1 : </li></ul><ul><li>Cells are broken down </li></ul><ul><li>to release DNA </li></ul><ul><li>If only a small amount of DNA is available it can be amplified using the polymerase chain reaction (PCR) </li></ul>
  19. 20. Stages of DNA Profiling <ul><li>Step 2: </li></ul><ul><li>The DNA is cut into fragments using restriction enzymes . </li></ul><ul><li>Each restriction enzyme cuts DNA at a specific base sequence. </li></ul>
  20. 21. Stages of DNA Profiling <ul><li>The sections of DNA that are cut out are called restriction fragments. </li></ul><ul><li>This yields thousands of restriction fragments of all different sizes because the base sequences being cut may be far apart (long fragment) or close together (short fragment). </li></ul>
  21. 22. Stages of DNA Profiling <ul><li>DNA is negatively charged so it is attracted to the positive end of the gel. </li></ul><ul><li>The shorter DNA fragments move faster than the longer fragments. </li></ul><ul><li>DNA is separated on basis of size. </li></ul>
  22. 23. Stages of DNA Profiling <ul><li>A radioactive material is added which combines with the DNA fragments to produce a fluorescent image. </li></ul><ul><li>A photographic copy of the DNA bands is obtained. </li></ul>
  23. 24. Stages of DNA Profiling <ul><li>Stage 4: </li></ul><ul><li>The pattern of fragment distribution is then analysed. </li></ul>
  24. 25. Crime <ul><li>Forensic science is the use of scientific knowledge in legal situations. </li></ul><ul><li>The DNA profile of each individual is highly specific. </li></ul><ul><li>The chances of two people having the same DNA profile is 30,000 million to 1 (except for identical twins). </li></ul>
  25. 26. Biological materials used for DNA profiling <ul><li>Blood </li></ul><ul><li>Hair </li></ul><ul><li>Saliva </li></ul><ul><li>Semen </li></ul><ul><li>Body tissue cells </li></ul>
  26. 27. DNA Profiling can solve crimes <ul><li>The pattern of the DNA profile is then compared with those of the victim and the suspect. </li></ul><ul><li>If the profile the suspect it provides strong evidence that the suspect was present at the crime scene. </li></ul><ul><li>If the profile do not match the suspect then that suspect may be eliminated from the enquiry. </li></ul>
  27. 28. Example <ul><li>A violent murder occurred. </li></ul><ul><li>The forensics team retrieved a blood sample from the crime scene. </li></ul><ul><li>They prepared DNA profiles of the blood sample, the victim and a suspect as follows: </li></ul>
  28. 29. Was the suspect at the crime scene? Suspects Profile Blood sample from crime scene Victims profile
  29. 30. References <ul><li>Molecular Cell Biology By Heavy F.Lodish, Arnold Berk. </li></ul><ul><li>DNA Fingerprinting an introduction By Sergio D.J Pena. </li></ul><ul><li>Principle of Biochemistry By Leincher. </li></ul><ul><li>DNA Fingerprinting and Profiling By Jorg T.Epplen. </li></ul>