Snowflack PhD wwwedvotekcom EDVOTEK The Biotechnology Education Company Celebrating OVER 30 years of science education Todays Experiment DNA Fingerprinting Many types of evidence is found at crime scenes ID: 918220
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DNA InvestigatorsDanielle R. Snowflack, Ph.D.www.edvotek.com
Slide2EDVOTEKThe Biotechnology Education Company
Celebrating OVER 30 years
of science education!
Slide3Today’s Experiment: DNA FingerprintingMany types of evidence is found at crime scenesForensic scientists use DNA analysis to analyze biological evidenceToday’s Experiments: Forensic DNA Fingerprinting Kits S-51 and 109
Slide4What is Forensic Science?Forensic science (or forensics) is the application of scientific knowledge to answer questions of interest within the legal system.Evidence from accidents and crime scenes is collected and analyzed by forensic scientists.Forensic scientists act as expert witnesses.Cat. # 119
Slide5Forensic Scientists Use Techniques from Many Scientific DisciplinesSouthern BlottingPolymerase Chain Reaction (PCR)
Blood Typing
Anthropology
– Analyze remains in advanced stages of decomposition
Genetics/Molecular Biology
– Uses biological material to determine serological and DNA profiles
Toxicology
– Identifies poisons, drugs and/or alcohol in tissues and body fluids.
Chemistry
– Analysis of trace physical evidence
Pathology
– Determine cause of death post-mortem
Clockwise from top: #140,
#502-504, #540
Slide6Forensic Science Lessons Engage Critical Thinking and Literacy SkillsRead witness statements and police reportAnalyze evidence using forensic science techniques Write a persuasive essay using the evidence from the written documents and the biological and physical tests.
Slide7A Break-in at the Lab!A scientist returned to her lab to find someone had broken in and stolen her research on a groundbreaking vaccine.Luckily, the police found evidence at the crime scene. Several suspects have been identified.As a forensic scientist, you have been commissioned to analyze the samples.For information on forensic blood testing please check out our past live stream!
Slide8Samples: dye, protein, RNA, DNAAgaroseElectrophoresis BufferElectrophoresis Apparatus
D.C. power source
Micropipet
What Do I Need to Perform Electrophoresis Experiments?
Slide9Summary of Electrophoresis
Slide10Casting the Agarose Gelhttps://youtu.be/EZjNuqSEPbY
Slide11Preparing for Electrophoresishttps://youtu.be/lgmq_HsuZIU
Slide12Variable Micropipette 20-200Top Gel: Dye SamplesBottom Gel: DNA SamplesDuoSource
150
M12 Complete Electrophoresis Package
Let’s run our gel!
Slide13Electrophoresis Chambers for Classrooms of all SizesCat. # 502Model M12
Two gels
Cat. # 515
Model M36
Six gels
Slide14Power Supplies Provide Current for ElectrophoresisCat. #5010QuadraSource™(10-300V)
Cat. #509
DuoSource
™
150
(75/150 V)
Slide15Introducing the Edvotek EDGE™
Slide16DNA is Isolated from Crime Scene SamplesCell membranes are disrupted to release its intracellular components. The resulting “lysate” consists of cytoplasm, metabolites, DNA, RNA, proteins and organelles.Want to learn more about forensic blood testing? Check out our past live stream!
Slide17DNA Sequences are UniqueThe chances of two individuals having exactly the same DNA profile is ~30,000 million to one Single Nucleotide Polymorphisms (SNPs) Restriction Fragment Length Polymorphisms (RFLPs)DNA profiling is a forensic technique used to identify individuals by analyzing differences within DNA.
CODIS – Combined DNA Index System
Slide18RFLPs Are Used as Landmarks for DNA FingerprintingRestriction Fragment Length Polymorphisms (or RFLPs) are heritable differences in the nucleotide sequence.Some RFLPS add a restriction enzyme cut site to the DNA.
Cat. # 109
A
B
Slide19RFLPs Are Used as Landmarks for DNA FingerprintingVariable Number of Tandem Repeats (or VNTRs) comprise short, repetitive DNA sequences present in multiple copies between two restriction sites15-35 base pair sequences
VNTRs appear between five and 100 times.
Cat. # 334
Slide20PCR Amplifies Specific DNA SequencesDenaturation (94°C) Double-stranded DNA is “unzipped” into single strands.Annealing (40-65°C) Primers base pair with the target DNA sequence. Extension (72°C)
Taq
polymerase extends the primer and synthesizes a new strand of DNA.
Cat. #541
Slide21DNA Fingerprinting is Used to Solve CrimesForensic scientists identified a biological sample at the scene of a crime.DNA was extracted from the sample, amplified by PCR and digested with restriction endonucleases to create a DNA Fingerprint.A match suggests that the suspect was at the crime scene.Cat. # 109
Cat. #130
Slide22Modern Approaches to DNA Fingerprinting AnalysisFamilial relationships can be determined by examining a person’s DNA profile.
1 – Standard DNA Fragments
2 – Mother’s DNA Digest
3 – Child’s DNA Digest
4 – Father 1 DNA Digest
5 – Father 2 DNA Digest
(Cat. #114)
Slide23The Genetic DetectiveThe Golden State Killer was found using familial DNA analysisFamily members uploaded sequences to genetic genealogy sitesForensic scientists uploaded crime scene DNA to identify familial connectionsTopic for discussion: Is it ethical to use this information to identify potential suspects? Do your family members have the right to privacy if you upload your DNA information?
Slide24Summary of Electrophoresis
Slide25Electrophoresis Separates DNA Fragments By SizeSamples are loaded into the wells, and an electrical current is passed through the gel. The sugar-phosphate backbone of DNA has a strong negative charge.The current drives the DNA through the gel towards the positive electrode.
Slide26Electrophoresis Separates DNA Fragments By SizeSmall DNA fragments move through pores easily, but large DNA fragments have a more difficult time squeezing through the tunnels. The DNA separates into distinct zones based on size.
Slide27Electrophoresis Separates DNA Fragments By SizeDNA is clear and colorless.After the current is stopped, the bands can be visualized using a stain that sticks to DNA. FlashBlueTM StainSybrSafe™ DNA Stain
Slide28Results and ConclusionsA match provides strong evidence that the suspect was present at the crime scene. Alone, this evidence does not prove the suspect committed the crime.If a suspect’s DNA profile does not match that of the crime scene, that person may be eliminated from the inquiry.
Slide29DNA Fingerprinting is an Important Techique in the Forensic Toolbox
Forensic science is the application of scientific methodology to answer legal questions.
DNA Fingerprinting identifies heritable differences in an individual’s DNA.
Data from crime scene evidence can suggest that a suspect was at a crime scene.
Results are used as evidence in the court of law.
Slide30EDVOTEK, Inc.The Biotechnology Education Company
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