The first exam will be Thursday, March 15, and will be worth 15 percent of your grade for the course. If you will be absent that day, e-mail me by the end of the day on Friday, March 9, so that we can schedule your makeup exam.
You may not use your notes during the exam. You will not need a calculator.
The exam will consist of 20 questions. Each of your answers should consist of one to a few sentences. You may include drawings in your answers if they help you make your point. While there is no strict length limit, you may get points off for writing long, rambling answers that say the same thing over and over.
Here are some practice questions. Try answering them, then highlight the invisible text inside the red box (drag your cursor across it) to see my answer.
1. McDonald (2013) studied the Gpi gene in the amphipod crustacean Megalorchestia californiana on the Washington, Oregon and California coasts. He found that the Gpi100 allele was very common in southern California and became less common as you go further north, and he concluded that cold temperatures selected against Gpi100. There is another possible explanation for the difference in allele frequency between the locations that doesn’t involve selection; what is it and how would it give these results?
2. In one of the papers you read, Kong et al. (2012) estimated the mutation rate in humans. How did they do this? They found that the rate of new mutations varied among individuals; what was the main reason that some individuals had more new mutations than others?
3. You want to become a world's expert on random genetic drift in island populations of rats. What are the three most important things you would do to find scientific literature about this topic?
4. The spadefoot toad, Scaphiopus couchii, lives in southern New Mexico. Some toads live on dark rock and are dark colored; some live on white sand and are light colored. You want to know whether this difference in color is genetic. You don’t know whether any genes are involved, much less which genes. What experiment could you do to tell whether the difference in color between populations of toads from dark rock vs. white sand is genetic? What would the result be if the difference is not genetic?
5. In one of the papers you read, Berry et al. (1991) measured DNA sequence polymorphism on the fourth chromosome of two species of Drosophila and found that the fourth chromosome had much less polymorphism than other chromosomes. What is this evidence of? Why?
6. Some people have wet, sticky earwax; other people have dry, crumbly earwax. This is caused by variation at a single gene with two alleles. The allele for wet earwax (W) is dominant over the dry allele (d). Right now, the frequency of W is about 90% in the United States. What do you expect to happen to the frequency of W in the United States over the next 100 years? Why?
7. Flies in the species Drosophila heteroneura have their eyes on the end of long stalks. Some individuals have longer stalks than others. Without using any kind of DNA data, what kind of experiments would you do to tell whether this variation in stalk length within a population is genetic? What result would you get if the variation is mostly genetic?
8. Janet Weiss of Denton University is studying a genetic polymorphism in cats, the long hair locus. Cats with the dominant L allele have short hair, while cats that are homozygous for the recessive l allele have long hair. She observes the hair length (long or short) on 100 cats from Hockessin, Delaware and estimates the allele frequency of l is 0.60. How did she do that? (You don’t have to do the calculations, just describe how the basic principle she used works.)
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