DNA fingerprinting is a technique used to analyze an organism's unique DNA composition as a characteristic marker. It works by examining variable number tandem repeats (VNTRs) in DNA, which provide a scientific marker for identity. The two main methods are Restriction Fragment Length Polymorphism (RFLP), which cuts, sorts, and photographs DNA fragments, and Polymerase Chain Reaction (PCR), which amplifies a small DNA sample. DNA fingerprinting is used to identify suspects in criminal cases like murders and rapes, determine parentage in legal disputes, and study non-human samples like wildlife crimes.

1. DNA Fingerprinting TAKE NOTES!!! Covers A lot in Chaper 8!

2. Summary Definition History How it works Different Methods of processing What it’s used for Draw Backs Final summary of presentation

3. QUESTION WHAT THE IS FORENSIC SCIENCE? WHAT THE IS DNA FINGERPRINTING?

4. Definition Forensic science: Intersection of Law and Science 1800’s: Photography 1900’s: Actual Fingertips Dna fingerprinting: Analysis of an organism’s unique DNA composition as a characteristic marker.

5. Question? Where did DNA fingerprinting come from?

6. History 1985: United Kingdom Sir Alex Jefferies Dr. peter Gill Dr. Dave Werrett Norborough Village Murder

7. History Cont. 1987: Florida USA Tommie Lee Andrews First person convicted of Rape Used a sample of Tommie’s blood and a sperm sample from the crime scene

8. Question How does it work?

9. DNA 101 Chemical Structure of DNA is always the same. IMPORTANT: THE ORDER OF THE BASE PAIRS IS DIFFERENT! 3 Billion Nucleotides form our 23 chromosomes IMPORTANT: EVERY CELL CONTAINS A COPY OF OUR DNA!

10. How Does it work? VNTR: variable number tandem repeats VNTR- recognition that variable numbers of repeated nucleotides can be found in dna and can be used for identification of individuals

11. How Does it Work Cont. VNTR’s: You get some from both parents IMPORTANT: NO PERSON HAS VNTR’S THAT ARE IDENTICAL TO THEIR FOLKS VNTR’s provide a scientific marker for identity. KEY ELEMENT!

12. What now Mr. Wizard? FIRST: GET DNA! Blood Skin Sperm Spit SECOND: Methods RFLP Dot Blot Analysis

13. RFLP RFLP: Restriction fragment length polymorphism Basically: Extract it, Chop it, Sort it, Photograph it

14. RFLP Cont. DNA is treated with Restriction Endonuclease Targets and cuts the Helix wherever a specific sequence appears Endonuclease is found in Bacteria like E.Coli Electrophoresis Negatively Charged DNA travels through a Gel towards a positively charged electrode. Smaller Fragments move faster! Gel is treated to get two single strands

15. RFLP Still Southern Blot Technique Probe it! Membrane is incubated with a radioactive or fluorescent strand of DNA Locus: Target Area of DNA Single Locus Probe Multi Locus Probe Hybridization Binding of the DNA fragment with it’s Probe Important: Probe will only bind to complementary parts! Everything else washed off!

16. RFLP: End! X-Ray Target dna is radioactive, it emits particles to make an image! Autoradiograph

17. Question What is needed to complete the dot blot analysis?

18. PCR Polymerase Chain Reaction Basically: Take a small sample of DNA and use a Thermal Cycler to multiply the sample. Warning! If you start with the wrong sample you are screwed!

19. PCR Locate the portion of DNA needed to study Thermal Cycler Enzyme: TAQ Polymerase DNA Nucleotides Cycle of Heat and Cold Thermal Cycler causes the DNA to separate and Replicate. PCR Key Element of Dot Blot Analysis.

20. Dot Blot Analysis Because of PCR the samples are identical and Electrophoresis is not needed. Each dot on the analysis strip has a different DNA probe Probe is a enzyme complex that can turn a colorless substrate into a colored one Probe is chemically reactive not RADIOACTIVE

21. Dot Blot Cont. Because human antibody alleles are different, the probability of a match can be concluded. Important! The dot sheet has a control dot, if it does not change color there wasn’t enough DNA

22. Almost done!

23. Just a recap Definition History (Briefly) VNTR’s RFLP PCR Dot Blot Analysis

24. Question what do we use DNA fingerprinting for?

25. Murders Colin pitchfork First guy to get convicted Sir Alex Jefferies Norborough Village Murder

26. Rape 1987: Tommie Lee Andrews 1988: Victor Lopez Faulty eye witness Women thought the attacker was black test by swapping vaginal cells and testing sperm samples

27. Parental issues Mitochondrial DNA: inherited from the mother only (cytoplasma of the egg) Remains the same Generation to Generation Traced through maternal line

28. Non Human Issues American and Asian Ginseng American: Boosts energy Asian: Calm nerves Pennsylvania: Bear was illegally killed Pregnant Sow DNA from den and check station

29. Setting Convicts Free Innocent Protection Act of 2001 Convicts access to DNA testing Prohibits states from destroying Biological evidence Kirk Bloodsworth

30. Drawbacks Collecting samples High temperatures can degrade DNA Bacteria Moisture Human Error Sneezes, improper storage, failure to label samples Chain of Custody Collection of evidence must be systematically recorded and access to evidence must be controlled

31. Final summary Methods, Definitions, History What it’s used for Draw backs THANKS FOR YOUR PARTICIPATION!

32. REFERENCES Lecture 7: A few famous cases involving DNA Evidence . March 2007 http://nitro. biosci . arizona .edu/courses/EEB195-2007/Lecture07/Lecture07.html Baden, Michael. DNA Profiling . http://www. kathyreichs . com/dnaprofiling .htm

33. REFERENCES CONT. CHAPTER 8 IN THE TEXT BOOK http://www.flickr.com/photos/davipt/228669699/ http://www.untangledlife.com/wibrary/wp-content/upload/sperm_untangled%20life.jpg http://www.admit-one.net/webimages/mrwizard.jpg