Lab 15

Question 1

In PCR, What is happening at each of the following temperatures in the thermal cycling program?

Answer 1

95 C - denaturation, denatures DNA to break it down
60 C - annealing, binds template to primer
72 C - extension, pulls nucleotides and adds to the DNA

Question 2

The TPOX forward primer has yellow fluorescent tag attached to it. Based on your understanding of PCR, would it be more logical to attach this to the 5’ or 3’ end of the primer?

Answer 2

5’ end so tag will not block extension

Question 3

What types of environmental factors will determine whether a DNA sample is usable or not?

Answer 3

Temperature, contamination, location, and surrounding chemicals

Question 4

What is meant by “contamination”?

Answer 4

Alternative molecules or genetic material is present that shouldn’t be or that vary from target persons genetic material

Question 5

What are some precautions that law enforcement officers are asked to take to prevent contamination of the DNA evidence?

Answer 5

Gloves are needed, don’t touch, no non-law enforcement disposable instruments not permitted

Question 6

What are “elimination samples”?

Answer 6

Voluntary collected DNA of those not involved in the crime

Question 7

There are several interesting factors that can cause a population to have a level of heterozygosity that is lower than normal for its species. What factors can you think that would reduce H in a population of organisms?

Answer 7

Inbreeding