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Sickle Cell Anemia - Form III Heterozygote Advantage?

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TAB OR USE THE MOUSE Between the fields....

You are encouraged to work in small groups (pairs or threes). You will only have to submit one "paper" per group (with all the names!)

Answer the questions as best you can. The boxes will expand as you type if you need more space. (Don't worry if it is a one word answer. The box size is standard.)


Class Period

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Read the following pages

Read and try and answer the questions at

(Note-you can "cheat" and have it fill in the mathematical answers-let's face it, we haven't done Hardy-Weinberg yet!)

Question 1:  Given what you know about evolution, how can a deleterious gene, such as the one for sickle cell anemia remain in a population at such a high level?

Question 2: Imagine you took a large population of Africans from the malaria zone and moved them to an area without malaria. What would you imagine would happen to the frequency of the gene for sickle cell anemia in the absence of malaria? In practice this was done by the institution of slavery. However, some slaves were kept in tropical and sub-tropical areas that still experienced malaria, while others were taken to areas free of the parasite. Remember slavery was not only a US institution, but was common in the Caribbean and Central and South America. After slavery the former slaves moved, in many cases north, away from the malaria zones. Discuss how these migrations, both forced and voluntary, may have effected the frequency of the gene for sickle cell anemia in North and South America. 


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