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

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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