Information for teachers

1. Information for teachers • The tidbit “The Prospect Puppy Burglary” suits nicely as a closure of lessons about DNA, DNA structure, replication … • Chapter 7 as a preparation supports performance of students • It is a very active and flexible tidbit • Activities: think and share, clicker questions, gel labeling and final group discussion. • Potential misconceptions can be corrected, especially with activity # 2 and 4 • Homework with different tasks aims higher in Bloom’s taxonomy • Flexibility: Activity #2 and 4 in particular leave space for discussions and additional questions if you have longer than the planned 20 minutes • #2 and 4 can be assessed as clicker questions in bigger class room/lecture halls, but also as one-to-one/in pairs with computers in smaller classes, or a group discussion with show of hands/answer cards • Preparation: colored print-out of worksheet, clickers

2. CSI:NH The Prospect Puppy Burglary CSI New Haven: Canine Special Investigators

3. CSI:NH The Crime Scene & Suspects • A prize puppy has been stolen from an apartment on Prospect Hill. The NHPD has arrested three possible suspects after collecting witness statements from the scene: • Suspect A was seen leaving the apartment in the early morning • Suspect B has been seen taking the dog for a walk over the last week • Suspect C crashed his/her car while leaving the parking lot that night

4. CSI:NH Your task: • To use DNA profiling to prepare a police report to convict the thief in court • You will discuss: • What DNA profiling is • Why & when we use it • Which samples to collect • Which part of DNA is used to differentiate people • Techniques used to examine DNA differences • How to read a DNA profile gel

5. CSI:NH Activity Number 1: What is DNA profiling and how is it useful in the police force? Where else might we employ it? Write your answer to this question in the space provided on the worksheet

6. CSI:NH Activity Number 2: You are the forensic scientist and need to pick a sample to get DNA from. Which sample will you pick? A – Blood which was on the broken glass of the door B – Saliva found on a spoon in a coffee mug C – Bunch of hair sticking to broken glass of door D – Any of the above E - Battery cells found in the room

7. CSI:NH • Blood • Red blood cells have no nuclei and so they contain no DNA. • The DNA found when blood is tested comes from the white blood cells. • Using modern techniques, each type of fluid or tissue in the question yields enough usable DNA for testing • Click to continue

8. CSI:NH • Saliva • Saliva does not contain cells, but as it passes through the salivary ducts, and washes around the mouth, it picks up cells. • Using modern techniques, each type of fluid or tissue yields enough usable DNA for testing • Click to continue

9. CSI:NH • Hair • Hair does not contain cells, but hair follicles do which can be used for DNA extraction. • Using modern techniques, each type of fluid or tissue yields enough usable DNA for testing • Click to continue

10. CSI:NH • Any of the above • The DNA found when blood is tested comes from the white blood cells, as red blood cells have no nucleus. • Saliva does not contain cells, but as it passes through the salivary ducts, and washes around the mouth, it picks up cells. • Hair does not contain cells, but hair follicles do which can be used for DNA extraction. • Using modern techniques, each type of fluid or tissue yields enough usable DNA for testing • Click to continue

11. CSI:NH Battery cells Well, try again!

12. CSI:NH NHPD Memo - PCR • To amplify small starting samples of DNA you should use PCR. • PCR reactions use primers complementary to your sequence of interest to amplify these regions. • PCR reactions are based on a cycle of these steps: http://www.biologymad.com/master.html?http://www.biologymad.com/geneticengineering/geneticengineering.htm

13. CSI:NH Activity Number 3: Select the correct sequence to perform your PCR reaction: A - Select primers, heat, anneal, replicate, extract DNA B - Select primers, replicate, heat, anneal, extract DNA C - Extract DNA, select primers, heat, anneal, replicate D - Extract DNA, select primers, heat, replicate, anneal

14. CSI:NH That’s not quite right – take another look and try again

15. CSI:NH Congratulations, you have amplified your DNA for profiling • Which regions of DNA will you use to catch the suspect? A – Single nucleotide polymorphisms (SNPs) B – Short tandem repeats (STRs) C – Chromosome translocations D – Not sure, let me look in my training manual! Activity Number 4

16. CSI:NH Single nucleotide polymorphisms (SNPs) SNPs are single base changes that are common throughout the genome They are inherited and can be used to define people as belonging to certain groups Click to try again

17. CSI:NH Click to continue

18. CSI:NH Chromosome translocations Translocations occur when DNA is copied badly and one arm of a chromosome ends up being switched to another They are rare events in the genome and often lead to large problems in development Click to try again

19. CSI:NH Activity Number 5: • You perform gel electrophoresis with the PCR samples from the people from infographic 7.5 • Take one minute to match the labels to the correct part of the gel A .......... B .......... C .......... Person 1 Person 2 Person 3 …. repeats 6 …. repeats 4

20. CSI:NH Click to continue

21. CSI:NH Activity Number 5: A .......... B .......... C .......... Person 1 Person 2 Person 3 …. repeats 6 …. repeats 4 chromosome 7 Question: Which label did you put in box C? A- Person 2 B - 6 repeats C - Person 1 D - 4 repeats E - Person 3

22. CSI:NH hair sample from the crime scene DNA from the puppy’s owner blood sample from broken glass at the crime scene Activity Number 6 – name your suspect Suspect B Suspect C Suspect A • You have run the gel from the suspects and your supervisor would like you to tell him what you know about the suspects before he reveals who they are – take 5 minutes to discuss the questions on the next slide in a group • Take notes during your discussion – this will be important for your homework!

23. CSI:NH hair sample from the crime scene DNA from the puppy’s owner Blood sample from broken glass at the crime scene Suspect B Suspect C Suspect A Who is the puppy thief? Is one of the suspects related to the puppy’s owner? What gender do you think each suspect is? Where might the hair sample have come from?

24. CSI:NH hair sample from the crime scene DNA from the puppy’s owner Blood sample from broken glass at the crime scene Suspect B Suspect C Suspect A Who is the puppy thief? Is one of the suspects related to the puppy’s owner? Hint – think about how STRs might be inherited from the parents What gender do you think each suspect is? Hint – think about the sex defining chromosomes Where might the hair sample have come from?

25. CSI:NH Homework activity • Write a police report to be presented in court to convict your suspect • Make sure you include • Why you chose to do DNA profiling • What experimental steps you took • Which suspect you think is the thief, and why? • Explain why you eliminated the other suspects from the investigation • Is there any doubt in your investigation? How could you make yourself more certain?