Follow-Up Questions 1. Sickle cell is a lethal disease caused by being homozygou
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Question
Follow-Up Questions 1. Sickle cell is a lethal disease caused by being homozygous for the recessive sickle cell allele. Individuals that are affected have the genotype ss, while SS are totally unaffected and S are carriers of the allele, but also have an intermediate phenotype. Ss individuals do not die from sickle cell anemia because they have some normal erythrocytes and some sickled erythrocytes. This mode of inheritance is known as incomplete dominance because the dominant allele is not fully expressed over the recessive allele. With sickle cell disease being lethal in your late 20s, one would expect that the disease-causing alleles would quickly exit the population gene pool. However, in equatorial Africa, the allele persists and S individuals are common. In that part of the world, malaria caused by Plasmodium vivax is also relatively common. This organism infects erythrocytes causing malaria. Propose a hypothesis as to why the sickle cell allele persists in the population at that part of the world and why Sr individuals would have an advantage In White Sands National Monument there are ponds that contain members of the desert pupfish population. Currently, this desert is receiving less average rainfall than normal, which is causing a contraction of the ponds. It is thought that eventually the ponds will shrink until they form two distinct ponds. What type of speciation could potentially impact the desert pupfish? In your answer, provide the distinct steps of this kind of speciation. 2. 3. Do you think it is possible for humans to undergo allopatric speciation? Explain.Explanation / Answer
answer to question 1 :
sickle cell allele persists in the population at that part of the world, beause this allele has been adapted by the nature , by the pocess of natural selection , over the years , as it has been observed conferring resistance to malaria in those indivoiduals with Ss ( heterozygous ) for this trait .
Ss ( heterozygous individuals have an advantage because people with this genotype , have half of there blood cells (RBCs) as sickle cell shaped, which does not let the Plasmodium vivax to complete their life cycle in thses RBCs and the organism(P. vivax) dies and the individual is protected from MALIGNANT malaria . in south africa . where this malaria is very common .