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DNA FingerprintingDNA Fingerprinting
TAKE NOTES!!!Covers A lot in Chaper 8!
TAKE NOTES!!!Covers A lot in Chaper 8!
SummarySummary
Definition History How it works Different Methods of processing What it’s used for Draw Backs Final summary of presentation
Definition History How it works Different Methods of processing What it’s used for Draw Backs Final summary of presentation
QUESTIONQUESTION
WHAT THE IS FORENSIC SCIENCE?WHAT THE IS DNA FINGERPRINTING?
WHAT THE IS FORENSIC SCIENCE?WHAT THE IS DNA FINGERPRINTING?
DefinitionDefinition
Forensic science: Intersection of Law and Science1800’s: Photography1900’s: Actual Fingertips
Dna fingerprinting: Analysis of an organism’s unique DNA composition as a characteristic marker.
Forensic science: Intersection of Law and Science1800’s: Photography1900’s: Actual Fingertips
Dna fingerprinting: Analysis of an organism’s unique DNA composition as a characteristic marker.
Question?Question?
Where did DNA fingerprinting come from?
Where did DNA fingerprinting come from?
HistoryHistory
1985: United Kingdom
Sir Alex Jefferies Dr. peter Gill Dr. Dave Werrett Norborough
Village Murder
1985: United Kingdom
Sir Alex Jefferies Dr. peter Gill Dr. Dave Werrett Norborough
Village Murder
History Cont.History Cont.
1987: Florida USATommie Lee
AndrewsFirst person
convicted of RapeUsed a sample of
Tommie’s blood and a sperm sample from the crime scene
1987: Florida USATommie Lee
AndrewsFirst person
convicted of RapeUsed a sample of
Tommie’s blood and a sperm sample from the crime scene
QuestionQuestion
How does it work?How does it work?
DNA 101DNA 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!
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!
How Does it work?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
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
How Does it Work Cont.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!
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!
What now Mr. Wizard?What now Mr. Wizard?
FIRST: GET DNA!BloodSkinSpermSpit
SECOND: MethodsRFLPDot Blot Analysis
FIRST: GET DNA!BloodSkinSpermSpit
SECOND: MethodsRFLPDot Blot Analysis
RFLPRFLP
RFLP: Restriction fragment length polymorphism
Basically: Extract it, Chop it, Sort it, Photograph it
RFLP: Restriction fragment length polymorphism
Basically: Extract it, Chop it, Sort it, Photograph it
RFLP Cont.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
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
Negatively Charged DNA travels through a Gel towards a positively charged electrode.
Smaller Fragments move faster!
Gel is treated to get two single strands
RFLP StillRFLP Still
Southern Blot Technique
Probe it!Membrane is
incubated with a radioactive or fluorescent strand of DNA
Locus: Target Area of DNA
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!
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!
RFLP: End!RFLP: End!
X-RayTarget dna is
radioactive, it emits particles to make an image!
Autoradiograph
X-RayTarget dna is
radioactive, it emits particles to make an image!
Autoradiograph
QuestionQuestion
What is needed to complete the dot blot analysis?
What is needed to complete the dot blot analysis?
PCRPCR
Polymerase Chain ReactionBasically: 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!
Polymerase Chain ReactionBasically: 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!
PCRPCR
1) Locate the portion of DNA needed to study
2) Thermal Cycler1) Enzyme: TAQ
Polymerase2) DNA Nucleotides3) Cycle of Heat
and Cold
1) Locate the portion of DNA needed to study
2) Thermal Cycler1) Enzyme: TAQ
Polymerase2) DNA Nucleotides3) Cycle of Heat
and Cold
o Thermal Cycler causes the DNA to separate and Replicate.
o PCR Key Element of Dot Blot Analysis.
o Thermal Cycler causes the DNA to separate and Replicate.
o PCR Key Element of Dot Blot Analysis.
Dot Blot AnalysisDot Blot Analysis
Because of PCR the samples are identical and Electrophoresis is not needed.
Each dot on the analysis strip has a different DNA probeProbe is a enzyme complex that can
turn a colorless substrate into a colored one
Probe is chemically reactive not RADIOACTIVE
Because of PCR the samples are identical and Electrophoresis is not needed.
Each dot on the analysis strip has a different DNA probeProbe is a enzyme complex that can
turn a colorless substrate into a colored one
Probe is chemically reactive not RADIOACTIVE
Dot Blot Cont.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
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
Almost done!Almost done!
Just a recapJust a recap
DefinitionHistory (Briefly)VNTR’sRFLPPCRDot Blot Analysis
DefinitionHistory (Briefly)VNTR’sRFLPPCRDot Blot Analysis
QuestionQuestion
what do we use DNA fingerprinting for?
what do we use DNA fingerprinting for?
MurdersMurders
Colin pitchforkFirst guy to get
convicted Sir Alex Jefferies
Norborough Village Murder
Colin pitchforkFirst guy to get
convicted Sir Alex Jefferies
Norborough Village Murder
RapeRape
1987: Tommie Lee Andrews
1988: Victor LopezFaulty eye witnessWomen thought
the attacker was black
test by swapping vaginal cells and testing sperm samples
1987: Tommie Lee Andrews
1988: Victor LopezFaulty eye witnessWomen thought
the attacker was black
test by swapping vaginal cells and testing sperm samples
Parental issuesParental issues
Mitochondrial DNA: inherited from the mother only (cytoplasma of the egg)Remains the same
Generation to Generation
Traced through maternal line
Mitochondrial DNA: inherited from the mother only (cytoplasma of the egg)Remains the same
Generation to Generation
Traced through maternal line
Non Human IssuesNon Human Issues
American and Asian GinsengAmerican: Boosts
energyAsian: Calm nerves
Pennsylvania: Bear was illegally killedPregnant SowDNA from den and
check station
American and Asian GinsengAmerican: Boosts
energyAsian: Calm nerves
Pennsylvania: Bear was illegally killedPregnant SowDNA from den and
check station
Setting Convicts FreeSetting Convicts Free
Innocent Protection Act of 2001Convicts access to
DNA testingProhibits states
from destroying Biological evidence
Kirk Bloodsworth
Innocent Protection Act of 2001Convicts access to
DNA testingProhibits states
from destroying Biological evidence
Kirk Bloodsworth
DrawbacksDrawbacks
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
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
Final summaryFinal summary
Methods, Definitions, HistoryWhat it’s used forDraw backs
THANKS FOR YOUR PARTICIPATION!
Methods, Definitions, HistoryWhat it’s used forDraw backs
THANKS FOR YOUR PARTICIPATION!
REFERENCESREFERENCES
Lecture 7: A few famous cases involving DNA Evidence. March 2007http://nitro.biosci.arizona
.edu/courses/EEB195-2007/Lecture07/Lecture07.html
Baden, Michael. DNA Profiling. http://www.kathyreichs.com/dnaprofiling.htm
Lecture 7: A few famous cases involving DNA Evidence. March 2007http://nitro.biosci.arizona
.edu/courses/EEB195-2007/Lecture07/Lecture07.html
Baden, Michael. DNA Profiling. http://www.kathyreichs.com/dnaprofiling.htm
REFERENCES CONT.REFERENCES CONT.
CHAPTER 8 IN THE TEXT BOOK http://www.flickr.com/photos/davipt/228
669699/ http://www.untangledlife.com/wibrary/w
p-content/upload/sperm_untangled%20life.jpg
http://www.admit-one.net/webimages/mrwizard.jpg
CHAPTER 8 IN THE TEXT BOOK http://www.flickr.com/photos/davipt/228
669699/ http://www.untangledlife.com/wibrary/w
p-content/upload/sperm_untangled%20life.jpg
http://www.admit-one.net/webimages/mrwizard.jpg