Into The Jungle Ch 8

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Chapter 8 Tony Allison’s early life experiences in Kenya prepared him to make the sickle cell-malaria link partly because he was stuck with malaria, a disease that left a long lasting memory. Tony pieced together that there was a possibility that the HbS allele, in heterozygotes for sickle cell anemia, aided in some degree of resistance to malaria. The sickle cell mutation is a balanced polymorphism because the heterozygote has an advantage over either homozygote. The data shows that, in areas of high malaria content, about “26 percent more AS heterozygote children than AA homozygote children reached adulthood” (Carroll 160) which reveals one of the largest selective advantages ever measured for a single trait. Tony’s demonstration of human resistance to malaria is important to evolutionary biology because it proves that the agent of natural selection is still active. Also, his discovery is important to evolutionary biology because the degree of resistance is measurable and important in early life, there is a simple genetic resistance, and the direct association is provided and proven. Tony’s discovery is very unique because it shows an example of a mutation that may be beneficial instead of the stereotypical view that all mutations are harmful. The HbS mutation is harmful under most conditions, but in certain cases, such as this sickle cell-malaria link, it is proven that the HbS mutation may be helpful. Tony went to Kenya as a young child and experienced a disease that many fear with their lives. Malaria is very dangerous, but Tony discovered something while visiting that shifted scientific genetic views. Previously, sickle cell anemia did not have any true benefits, yet Tony researched deeply and found a link that is nearly unquestionable. The link shows that people who are heterozygous with sickle cell have proven to be able to survive more

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