1. How can DNA be used to solve Crimes?
DNA Evidence
How can DNA be used to solve Crimes?

2. Objective: Describe how DNA can be analyzed and used as evidence.
Do Now: Why is DNA considered circumstantial evidence?
In groups of 5 or less, work together on the DNA questions. Write all names and answers on loose-leaf paper. Hand in.
Closure: At a crime scene, list at least 3 places investigators should look for DNA evidence.

3. Objectives: Describe what DNA is and identify the different types of DNA
Do Now: Where can DNA come from? Brainstorm all evidence that may have DNA
**mDNA not in nucleus

4. Objectives: Describe what DNA is and identify the different types of DNA
What is DNA?
DNA contains genetic information.
Found on chromosomes located in the nucleus of our cells**
Individual Evidence
**mDNA not in nucleus

5. Made up of base pairs: (think of a bar code) A – T C – G
Objectives: Describe how DNA can be analyzed and used as evidence. Explain the importance of CODIS in forensic science.
Made up of base pairs: (think of a bar code)
A – T
C – G
The order of the base pairs determines the genetic code
CYTOSINE
THYMINE
GUANINE
ADENINE

6. Complimentary Base Pairing
AGTACG
TCATGC

7. Objectives: Describe how DNA can be analyzed and used as evidence
Objectives: Describe how DNA can be analyzed and used as evidence. Explain the importance of CODIS in forensic science.
Human DNA
50% of a person’s DNA comes from each parent
23 pairs (46 chromosomes) in nucleus of most cells*
1 chromosome in each pair is inherited from mother and other from the father
Every person has a different DNA
sequence expect identical twins.
**How can we distinguish between
identical twins apart?
*Except sperm and egg
**fingerprints (new research shows non coding DNA differences)
**copy number variants can be different in identical twins

8. Objectives: Describe the different types of DNA can be analyzed and used as evidence.
Types of Human DNA
NUCLEAR DNA: found in chromosomes
Used for DNA Fingerprinting
Unique to individual
MITOCHONDRIAL DNA: Found in mitochondria
Inherited from mother
Not unique
Example: bone, hair shaft

9. Objectives: Describe how DNA can be analyzed and used as evidence.
Why use mDNA?
More stable over time/conditions*
Can get more DNA if sample is limited
Can get DNA from a highly degraded source
*More stable because located in double membrane organelle

10. How is DNA used? Identify a victim
Objectives: Describe how DNA can be analyzed and used as evidence.
How is DNA used?
Identify a victim
Link or exclude suspect to crime scene/evidence
Link multiple crime scenes
Establish Maternity/Paternity

11. What Factors Affect DNA evidence
Objectives: Describe how DNA can be analyzed and used as evidence.
What Factors Affect DNA evidence
Heat, sunlight, moisture, bacteria, and mold (this was a major issue in the O.J. Simpson Case)
Not all DNA evidence will result in a usable DNA profile.
DNA testing cannot identify when the suspect was at the crime scene or for how long.

12. Objectives: Describe how DNA can be analyzed and used as evidence
Objectives: Describe how DNA can be analyzed and used as evidence. Explain the importance of CODIS in forensic science.
What is CODIS?
Electronic database of DNA profiles that can identify suspects.
DNA profiles from individuals convicted of certain crimes, such as rape, murder, and child abuse, are entered into CODIS and help identify possible suspects when no prior suspect existed.
Combined DNA Index System

13. Introduction to DNA Fingerprinting
Objectives: Describe how DNA can be analyzed and used as evidence. Explain the importance of CODIS in forensic science.
Introduction to DNA Fingerprinting
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14. Watch the video and then answer the questions.
Video Link:
1. When did DNA start to be an important tool in forensics? A s B. 1960s C. 1980s
2. What type of evidence does the FBI consider its most powerful tool? A. Fingerprints B. Blood C. DNA
3. What program is used to match DNA samples to possible contributors? A. CODIS B. AFIS C. DNA Code
4. What is it called when the program makes a match? A. Hot Hit B. Cold Hit C. Dead Hit
5. How many criminals have been convicted based on this software? A B C. 1,500

15. Do Now: What are some factors that degrade (affect) DNA?
Objectives: Describe the role of DNA in the O.J. Simpson case
Do Now: What are some factors that degrade (affect) DNA?

16. The answers are …
1. When did DNA start to be an important tool in forensics? A s B. 1960s C. 1980s
2. What type of evidence does the FBI consider its most powerful tool? A. Fingerprints B. Blood C. DNA
3. What program is used to match DNA samples to possible contributors? A. CODIS B. AFIS C. DNA Code
4. What is it called when the program makes a match? A. Hot Hit B. Cold Hit C. Dead Hit
5. How many criminals have been convicted based on this software? A B C. 1,500

17. http://law2.umkc.edu/faculty/projects/ftr ials/Simpson/Dna.htm
Objectives: Describe the role of DNA in the O.J. Simpson case
ials/Simpson/Dna.htm
Complete DNA and the O.J. Simpson case study
Closure: The DNA found at the scene only shows OJ was present for the crime. What other evidence could they/did they find to try to link him as their major suspect?
Link shows DNA results for each piece of evidence for OJ case

18. Do Now: What is a DNA Fingerprint?
Objectives: Describe how a DNA fingerprint is performed
Do Now: What is a DNA Fingerprint?
The method of identification based on an individuals DNA:

19. 2 Main Types of DNA Testing
Objectives: Describe how a DNA fingerprint is performed
2 Main Types of DNA Testing
RFLP: * analyzes variable lengths of DNA cut by restriction enzymes.
requires large amounts of DNA and no degradation
RFLP: Restriction Fragment Length Polymorphism.

20. Objectives: Describe how a DNA fingerprint is performed
Restriction enzymes: cut DNA at specific base sequences resulting in variable lengths of DNA

21. Objectives: Describe how a DNA fingerprint is performed
Gel Electrophoresis: Method of separating molecules of DNA within an electric field based on the size and charge of DNA fragments

22. Objectives: Describe how a DNA fingerprint is performed
mations/gelelectrophoresis.html
More probes taken, the better the match probability will be.
Denim blue jeans actually interfere with the restriction enzymes!

24. How are gel electrophoresis results analyzed?
Objectives: Describe how a DNA fingerprint is performed
How are gel electrophoresis results analyzed?

25. Objectives: Describe how a DNA fingerprint is performed
DNA and Paternity

26. Complete the following activities: Who are the parents
Objectives: Describe how a DNA fingerprint is performed
Complete the following activities:
Who are the parents
Which man is the father
Closure: If everyone gave their DNA to CODIS every substantial crime could be run through the CODIS program to produce cold hits. This would solve more crimes faster. Would you agree to giving your DNA to the government to run a program like that?

27. Do Now: What does a restriction enzyme do?
Objectives: Describe how a DNA fingerprint is performed
Do Now: What does a restriction enzyme do?

28. 2nd Main type of DNA testing:
Objectives: Describe how a DNA fingerprint is performed
2nd Main type of DNA testing:
PCR: (Polymerase Chain Reactions) specific sequences of DNA that have high variability (differences) are copied millions of times
Less DNA needed and can be partially degraded

29. Newest type of DNA testing:
Objectives: Describe how a DNA fingerprint is performed
Newest type of DNA testing:
STR: Evaluates specific short repeating regions (loci) within nuclear DNA
FBI uses 13 standard specific STR regions for CODIS

30. For 1 STR sequence at 1 locus
G-G-C-C-X-X-X-G-G-C-C-X-X..
G-G-G-C-C-X-X-G-G-C-C-X-X…..
STR
C-C-X-X-X-G-G
C-C-X-X-G-G
PCR amplify
STR region
well
Gel
electrophoresis
Person A
Forensic sample
This will be done 13 times

31. Objectives: Describe how a DNA fingerprint is performed
Complete STR profile
Capillary electrophoresis instrument used

32. STR match probabilities are 1 in a quintillion (1x1018) or more
Objectives: Describe how a DNA fingerprint is performed
STR match probabilities are 1 in a quintillion (1x1018) or more

33. Objectives: Describe how a DNA fingerprint is performed
Complete “The break in” activity and concepts of biotechnology reading. And hand in.
Closure: Name three different reasons why a DNA profile may be needed to identify a person.

34. Do Now: What is an advantage to PCR over RFLP?
Objectives: Construct a gel electrophoresis simulation and determine who committed the crime
Do Now: What is an advantage to PCR over RFLP?

35. Start the individual DNA Fingerprinting Lab and hand in.
Objectives: Construct a gel electrophoresis simulation and determine who committed the crime
Start the individual DNA Fingerprinting Lab and hand in.
Closure: If we only have 4 bases (AGCT) that our DNA is made up of, how can everyone's DNA be completely different? Hand in your closure/do now sheet.

36. Finish the individual DNA Fingerprinting Lab and hand in.
Objectives: Construct a gel electrophoresis simulation and determine who committed the crime
Do Now: Can any two people have the same DNA? Can any have the same mDNA?
Finish the individual DNA Fingerprinting Lab and hand in.
Closure: Do other animals have DNA?

37. Finish the individual DNA Fingerprinting Lab and hand in. (20min)
Objectives: Construct a gel electrophoresis simulation and determine who committed the crime
Do Now: There’s a copy of our entire DNA sequence in every cell of our body with one exception: red blood cells. But our sex cells only have ______ of our DNA.
Finish the individual DNA Fingerprinting Lab and hand in. (20min)

38. Complete the DNA profile review sheet. Hand it in.
Objectives: Construct a gel electrophoresis simulation and determine who committed the crime
Complete the DNA profile review sheet. Hand it in.
Closure: Besides determining suspects or paternity, what else can DNA be used for?

39. Objectives: Describe how a DNA fingerprint is performed
Do Now: Why does the DNA travel to the bottom of the gel electrophoresis chamber?
Watch the video and take notes on your handout. This will be due tomorrow when we finish the video.
Closure: What DNA did the suspect leave behind?

40. Do Now: What are the base pairs I DNA and how do they match up?
Objectives: Construct a gel electrophoresis simulation and determine who committed the crime
Do Now: What are the base pairs I DNA and how do they match up?
Start the group DNA profile lab and hand in.
Closure: One chromosome can have as little as 50 million base pairs or as much as 250 million base pairs. How many chromosomes do we have?

41. Do Now: What does the gel electrophoresis do?
Objectives: Construct a gel electrophoresis simulation and determine who committed the crime
Do Now: What does the gel electrophoresis do?
Complete the group DNA profile lab and hand in.
Closure: Check your grades. Write down what you are missing.