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dna fingerprinting powerpoint

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gohil sanjay bhagvanji

DNA fingerprinting was developed in 1984 by Alec J. Jeffrey at the University of Leicester. It involves analyzing variable number tandem repeats (VNTRs) in DNA to generate a unique profile for identifying individuals. DNA fingerprinting has six main steps: isolating DNA, cutting it with restriction enzymes, transferring fragments to nylon, probing with radioactive markers, and comparing the final fingerprint to other samples. This technique can solve crimes by matching DNA from a crime scene to suspects, determine paternity in inheritance cases, and has been used in famous cases like those involving Elizabeth Hurley and OJ Simpson.

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(DNA fingerprinting)
Historical background DNA fingerprinting was developed in 1984 by Alec. J. Jeffrey at the University of Leicester He was studying the gene of myoglobin. This is a picture of Alec. J. Jeffrey
What is DNA Fingerprinting? The chemical structure of everyone's DNA is the same. The only difference between people (or any animal) is the order of the base pairs. The information contained in DNA is determined primarily by the sequence of letters along the zipper. Structure of DNA
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 "POST" has a different meaning from "STOP" or "POTS," even though they use the same letters. i
Using these sequences, every person could be identified solely by the sequence of their base pairs  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. These patterns do not, however, give an individual "fingerprint," they are able to determine whether two DNA samples are from the same person, related people, or non- related people.
DNA Fingerprinting using VNTR'sOn some human chromosomes, a short sequence of DNA has been repeated a number of times.  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 ) identify the VNTR's for the DNA sequence of the repeat.
Making DNA Fingerprints DNA fingerprinting is a laboratory procedure that requires six steps: 1: Isolation of DNA. 2: Cutting, sizing, and sorting. Special enzymes called restriction enzymes are used to cut the DNA at specific places
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. 4-5: Probing. Adding radioactive or colored probes to the nylon sheet produces a pattern called the DNA fingerprint.
4-6: DNA fingerprint. The final DNA fingerprint is built by using several probes (5-10 or more) simultaneously.
Stages of DNA Profiling Stage 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)
Stages of DNA Profiling Step 2: The DNA is cut into fragments using restriction enzymes. Each restriction enzyme cuts DNA at a specific base sequence.
Stages of DNA Profiling The sections of DNA that are cut out are called restriction fragments. 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).
Stages of DNA Profiling Stage 3: Fragments are separated on the basis of size using a process called gel electrophoresis. DNA fragments are injected into wells and an electric current is applied along the gel.
Stages of DNA Profiling 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.
Stages of DNA Profiling A radioactive material is added which combines with the DNA fragments to produce a fluorescent image. A photographic copy of the DNA bands is obtained.
Crime Forensic science is the use of scientific knowledge in legal situations. The DNA profile of each individual is highly specific. The chances of two people having exactly the same DNA profile is 30,000 million to 1 (except for identical twins).
Biological materials used for DNA profiling Blood Hair Saliva Semen Body tissue cells DNA samples have been obtained from vaginal cells transferred to the outside of a condom during sexual intercourse.
DNA Profiling can solve crimes The pattern of the DNA profile is then compared with those of the victim and the suspect. If the profile matches the suspect it provides strong evidence that the suspect was present at the crime scene (NB:it does not prove they committed the crime). If the profile doesn’t match the suspect then that suspect may be eliminated from the enquiry.
Example A violent murder occurred. The forensics team retrieved a blood sample from the crime scene. They prepared DNA profiles of the blood sample, the victim and a suspect as follows:
Was the suspect at the crime scene? Suspects Profile Blood sample from crime scene Victims profile
Solving Medical Problems DNA profiles can be used to determine whether a particular person is the parent of a child. A childs paternity (father) and maternity(mother) can be determined. This information can be used in • Paternity suits • Inheritance cases • Immigration cases
Example: A 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.
Is this man the father of the child? Mother Child Man
Famous cases In 2002 Elizabeth Hurley used DNA profiling to prove that Steve Bing was the father of her child Damien
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.
DNA fingerprinting

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dna fingerprinting powerpoint

  • 2. Historical background DNA fingerprinting was developed in 1984 by Alec. J. Jeffrey at the University of Leicester He was studying the gene of myoglobin. This is a picture of Alec. J. Jeffrey
  • 3. What is DNA Fingerprinting? The chemical structure of everyone's DNA is the same. The only difference between people (or any animal) is the order of the base pairs. The information contained in DNA is determined primarily by the sequence of letters along the zipper. Structure of DNA
  • 4. 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 "POST" has a different meaning from "STOP" or "POTS," even though they use the same letters. i
  • 5. Using these sequences, every person could be identified solely by the sequence of their base pairs  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. These patterns do not, however, give an individual "fingerprint," they are able to determine whether two DNA samples are from the same person, related people, or non- related people.
  • 6. DNA Fingerprinting using VNTR'sOn some human chromosomes, a short sequence of DNA has been repeated a number of times.  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 ) identify the VNTR's for the DNA sequence of the repeat.
  • 7. Making DNA Fingerprints DNA fingerprinting is a laboratory procedure that requires six steps: 1: Isolation of DNA. 2: Cutting, sizing, and sorting. Special enzymes called restriction enzymes are used to cut the DNA at specific places
  • 8. 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. 4-5: Probing. Adding radioactive or colored probes to the nylon sheet produces a pattern called the DNA fingerprint.
  • 9. 4-6: DNA fingerprint. The final DNA fingerprint is built by using several probes (5-10 or more) simultaneously.
  • 10. Stages of DNA Profiling Stage 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)
  • 11. Stages of DNA Profiling Step 2: The DNA is cut into fragments using restriction enzymes. Each restriction enzyme cuts DNA at a specific base sequence.
  • 12. Stages of DNA Profiling The sections of DNA that are cut out are called restriction fragments. 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).
  • 13. Stages of DNA Profiling Stage 3: Fragments are separated on the basis of size using a process called gel electrophoresis. DNA fragments are injected into wells and an electric current is applied along the gel.
  • 14. Stages of DNA Profiling 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.
  • 15. Stages of DNA Profiling A radioactive material is added which combines with the DNA fragments to produce a fluorescent image. A photographic copy of the DNA bands is obtained.
  • 16. Crime Forensic science is the use of scientific knowledge in legal situations. The DNA profile of each individual is highly specific. The chances of two people having exactly the same DNA profile is 30,000 million to 1 (except for identical twins).
  • 17. Biological materials used for DNA profiling Blood Hair Saliva Semen Body tissue cells DNA samples have been obtained from vaginal cells transferred to the outside of a condom during sexual intercourse.
  • 18. DNA Profiling can solve crimes The pattern of the DNA profile is then compared with those of the victim and the suspect. If the profile matches the suspect it provides strong evidence that the suspect was present at the crime scene (NB:it does not prove they committed the crime). If the profile doesn’t match the suspect then that suspect may be eliminated from the enquiry.
  • 19. Example A violent murder occurred. The forensics team retrieved a blood sample from the crime scene. They prepared DNA profiles of the blood sample, the victim and a suspect as follows:
  • 20. Was the suspect at the crime scene? Suspects Profile Blood sample from crime scene Victims profile
  • 21. Solving Medical Problems DNA profiles can be used to determine whether a particular person is the parent of a child. A childs paternity (father) and maternity(mother) can be determined. This information can be used in • Paternity suits • Inheritance cases • Immigration cases
  • 22. Example: A 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.
  • 23. Is this man the father of the child? Mother Child Man
  • 24. Famous cases In 2002 Elizabeth Hurley used DNA profiling to prove that Steve Bing was the father of her child Damien
  • 25. 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.