BIOL 103 Home

Mutant 2. Jean Grey

1. Jean Grey's challenge: "Our Westchester School for Mutants is recruiting new students. Find me a new Mutant to apply. Define the applicant's mutant powers; whether the trait is dominant or recessive; the allele frequencies (p and q); and the fraction of the population that is homozygous (pure-breeding) for this trait."

What do you say?

2. The von Kleist family shows frequent appearance of Huntington's disease, a dominant trait.

a. From the information you can find in the text of Galapagos, draw the family tree of the captain von Kleist and his brother. Define and include an appropriate genotype designation for each person.

b. Consider a hypothetical daughter of Siegfried. What are the possible genotypes for her and what chance does she have of having the disease?

c. You are a genetic counselor, and you are visited by a young person whose father died of Huntington’s disease who was planning to marry someone who did not have the disease in her family. What would you advise them and why? A DNA test now exists to detect whether one carries the Huntington allele. How would this change your advice?

3. Researchers have identified an allele of a gene that confers resistance to HIV virus, the cause of AIDS. The allele is a version of the CCR5 gene that has part of its sequence deleted (allele CCR5-delta 32). THe gene makes a cell surface protein that HIV needs to infect a cell.

The CCR5-delta 32 allele is present at a frequency of 0.12 in some populations. Persons who are homozygous recessive (aa) show virtually complete resistance to HIV, and those who are heterozygous (Aa) have 78% lower risk of HIV infection. Those who are homozygous dominant (AA) have no resistance to HIV.

Find the percentages of the population that are:
--Carriers (Aa) and thus partly protected from AIDS.
--Homozygous (aa) thus completely resistant to AIDS.
--Normal (AA) thus completely susceptible to AIDS.

4. Explain how each of the following traits is determined by genes and/or environment:

* Gender differences
* Diabetes
* Spoken language

5. Vonnegut offers several hypotheses to explain how tortoises traveled to Galapagos. Select a DIFFERENT example of a hypothesis in the story that was NOT discussed in class.

a. State the hypothesis, and how it arose in the story.

b. Explain how the characters use evidence either to support or refute the hypothesis.

6. Suppose a human evolved the ability to absorb solar energy through photosynthesis, instead of eating food.

a. What would we call the kind of evolution that generates a "plantoid" person?

b. Would the person be able to interbreed with plants?

7. Suppose a virus infecting humans kills 400 out of 600 in one year, but infecting Mutants it kills 30 out of 100 in one year. How long till the last human dies? The last Mutant?