BIO 621 S10
Exam I
Name______________________
1. Selection of mutagen is an important decision to be made when conducting any forward genetic
screen. For each of the following mutagens, indicate the type of lesions expected, and describe the
strengths and weaknesses of using each in a screen.
a. Ethyl methanesulfonate (EMS)
b. X-rays (ionizing radiation)
c. Transposable element
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BIO 621 S10
Exam I
Name______________________
2.a. Describe all possible effects that a point mutation in the coding region of a gene may have on the
gene product.
b. Of the changes that can occur in the coding region, which is most likely to result in a null
mutation? Justify your answer.
c. How would you determine genetically (not molecularly) if an induced point mutation is a null
allele?
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BIO 621 S10
Exam I
Name______________________
3. The complementation test is a powerful and important genetic tool. If you are given two strains of
mice with point mutations that cause black coat color as recessive, explain how you would conduct a
complementation test, including the possible test results and how you would interpret them. Provide a
diagram of the chromosome for the parents and progeny for each possible outcome of the
complementation test.
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BIO 621 S10
Exam I
Name______________________
4. Although we think of the complementation test as a clear and unambiguous analytical technique,
there are a number of examples of mechanisms by which the classical interpretation of
complementation tests results in a misleading outcome. Describe and explain three examples of genetic
situations in which complementation tests can be or have been misleading.
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BIO 621 S10
Exam I
Name______________________
5. Mutations in the Drosophila signaling protein hedgehog gene (hh) result in recessive embryonic
lethality, yet we know that many signaling proteins are pleiotropic. What does pleiotropic mean?
Design an experiment that allows you to determine the role of hh in wing development, a process that
occurs well after embryogenesis. Include all tools you need to conduct the experiment, possible results,
and how you interpret them. It may be useful to use diagrams.
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BIO 621 S10
Exam I
Name______________________
6. Explain how one would use the “phiC31 system” to integrate transgenes, including a diagram. Be
sure to name all necessary tools. What is the major advantage to using this system over other
transgenesis methods?
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BIO 621 S10
Exam I
Name______________________
7. Because of the pleiotropy of the mouse Sonic hedgehog gene (Shh), misexpression during embryonic
development results in lethality. Based on suggestions from flies, you hypothesize that Shh
misexpression will have a detrimental influence on learning and memory in the adult mouse. Describe
how you would generate the mice that would allow you to test your hypothesis. You may want to
include a diagram. Hint: GAL4/UAS expression is NOT available for mice.
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