DNA Fingerprinting TAKE NOTES Covers A lot in

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

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

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

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

Question? Where did DNA fingerprinting come from?

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

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

Question How does it work?

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

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

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

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

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

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

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

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

Question What is needed to complete the dot blot analysis?

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

PCR 1) Locate the portion of DNA needed to study 2) Thermal Cycler 1) Enzyme: TAQ Polymerase 2) DNA Nucleotides 3) Cycle of Heat and Cold o Thermal Cycler causes the DNA to separate and Replicate. o PCR Key Element of Dot Blot Analysis.

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

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

Almost done!

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

Question what do we use DNA fingerprinting for?

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

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

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

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

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

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

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

REFERENCES G Lecture 7: A few famous cases involving DNA Evidence. March 2007 G http: //nitro. biosci. arizona. edu/courses/EEB 1952007/Lecture 07. html G Baden, Michael. DNA Profiling. G http: //www. kathyreichs. com/dnaprofiling. htm

REFERENCES CONT. G CHAPTER 8 IN THE TEXT BOOK G http: //www. flickr. com/photos/davipt/2286 69699/ G http: //www. untangledlife. com/wibrary/wpcontent/upload/sperm_untangled%20 life. jpg G http: //www. admitone. net/webimages/mrwizard. jpg