Concept explainers
To write: A short essay to explain the molecular and cellular events leading to the heterozygotes individuals in sickle cell trait leading to the individual and population levels of biological organisation. .
Introduction:
Sickle cell disease is the most commonly occurring recessive inherited disorder found in African – Americans with an incidence of 1/400 and a carrier frequency of 1/10. It is caused due to the sickle cell allele that results in the structural and functional abnormality in normal haemoglobin. A point mutation that causes the substitution of glutamic acid by valine at 6th position of β-globin chain of haemoglobin is the main cause. The homozygous recessive individuals suffer severely from the disease; however the heterozygous carriers have the benefit of killing the malarial parasites in malaria rich regions of the World.
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- In one type of hemoglobin variant, lysine EF6 is replaced by an aspartic acid residue. What would be the effects of this mutation on the affinity of the hemoglobin for 2,3 BPG and oxygen? The affinity for 2,3-BPG would increase, and for oxygen would decrease. The affinity for 2,3-BPG would decrease, and for oxygen would decrease. The affinities for 2,3-BPG and for oxygen would be unaffected. The affinity for 2,3-BPG would increase, and for oxygen would increase. The affinity for 2,3-BPG would decrease, and for oxygen would increase.arrow_forwardSickle-cell anemia is an interesting genetic disease. Normal homozygous individials (SS) have normal blood cells that are easily infected with the malarial parasite. Thus, many of these individuals become very ill from the parasite and many die. Individuals homozygous for the sickle-cell trait (ss) have red blood cells that readily collapse when deoxygenated. Although malaria cannot grow in these red blood cells, individuals often die because of the genetic defect. However, individuals with the heterozygous condition (Ss) have some sickling of red blood cells, but generally not enough to cause mortality. In addition, malaria cannot survive well within these "partially defective" red blood cells. Thus, heterozygotes tend to survive better than either of the homozygous conditions. 11% of an African population is born with a severe form of sickle-cell anemia (ss), What percentage of the population will be more resistant to malaria because they are heterozygous (Ss) for the sickle-cell…arrow_forwardSickle-cell anemia is an interesting genetic disease. Normal homozygous individials (SS) have normal blood cells that are easily infected with the malarial parasite. Thus, many of these individuals become very ill from the parasite and many die. Individuals homozygous for the sickle-cell trait (ss) have red blood cells that readily collapse when deoxygenated. Although malaria cannot grow in these red blood cells, individuals often die because of the genetic defect. However, individuals with the heterozygous condition (Ss) have some sickling of red blood cells, but generally not enough to cause mortality. In addition, malaria cannot survive well within these "partially defective" red blood cells. Thus, heterozygotes tend to survive better than either of the homozygous conditions. 11% of an African population is born with a severe form of sickle-cell anemia (ss), What is the frequency of the dominant allele? Please show your work in order to receive credit.arrow_forward
- Sickle-cell anemia is an interesting genetic disease. Normal homozygous individials (SS) have normal blood cells that are easily infected with the malarial parasite. Thus, many of these individuals become very ill from the parasite and many die. Individuals homozygous for the sickle-cell trait (ss) have red blood cells that readily collapse when deoxygenated. Although malaria cannot grow in these red blood cells, individuals often die because of this genetic defect causes deformation of red blood cells. However, individuals with the heterozygous condition (Ss) have some sickling of red blood cells, but generally not enough to cause mortality. In addition, malaria cannot survive well within these "partially defective" red blood cells. Thus, heterozygotes tend to survive better than either of the homozygous conditions. Assuming HWE, if 9% of an African population is born with a severe form of sickle-cell anemia (ss), what percentage of the population will be more resistant to malaria…arrow_forwardSickle-cell anemia is an interesting genetic disease. Normal homozygous individials (SS) have normal blood cells that are easily infected with the malarial parasite. Thus, many of these individuals become very ill from the parasite and many die. Individuals homozygous for the sickle-cell trait (ss) have red blood cells that readily collapse when deoxygenated. Although malaria cannot grow in these red blood cells, individuals often die because of the genetic defect. However, individuals with the heterozygous condition (Ss) have some sickling of red blood cells, but generally not enough to cause mortality. In addition, malaria cannot survive well within these "partially defective" red blood cells. Thus, heterozygotes tend to survive better than either of the homozygous conditions. 11% of an African population is born with a severe form of sickle-cell anemia (ss), What is the frequency of the recessive allele? Please show your work in orderarrow_forwardWhen human hemoglobin undergoes a mutation, the mutant protein usually does not replace all of the normal HbA in the red blood cells or erythrocytes of the individual. The erythro- cytes contain mixtures of varying amounts of both HbA and the mutant protein depending on the mutation and the individual. Hb Yakima is a mutant human Hb with an Asp-(B99)His mutation. The diagram on the right shows that Hb Yakima was separated by DEAE-cellulose chromatography from HbA with a 0 – 0.1 M linear gradient of NaCl buffered to pH 8.3. Why is chromatog- raphy carried out at pH 8.3? If the isoelectric point of HbA is 6.85, what is the change in total charge caused by the mutation?How does the change in charge explain the chromatography elution profile of the Hb Yakima/HbA mixture? 1,5 -Hb-A Hb -Yakima 1.0 0.5- 20 40 60 80 00 Fraction number O.D578 nmarrow_forward
- In a region of Africa, where malaria is prevalent, 40% of the population are found to have sickle-cell anemia. The disease is caused by an abnormal hemoglobin that is found in both homozygotes (S2S2) and heterozygotes (S1S2). Many homozygotes (S2S2) suffer from anemia and often die. Heterozygotes (S1S2) incur a much less debilitating malady called "sickling trait". Approximately 3% of the people with abnormal hemoglobin are homozygotes (1.2\% of the entire population). The fitness of the S2S2 homozygotes is only 1/4 that of the heterozygotes. Where malaria is prevalent, heterozygotes exhibit overdominance with respect to fitness. How would you calculate relative fitness of the S1S1 homozygotes if you're assuming the population is at an equilibrium frequency for S2?arrow_forwardPlease helparrow_forwardNormal Hgb is referred to as HbA and contains 4 subunits, 2 α-globin chains and 2 β-globin chains, arranged as two dimers of αβ. In Sickle Cell Disease, both β-globin chains are altered in the dimers (αβS/αβS). Q3: Which level of structure does the αβ/αβ and αβS/αβS in HbA and HbS describe?arrow_forward
- Please answer asap and in shortarrow_forwardBACKGROUND Sickle cell disease is caused by a change in the gene for hemoglobin, which is the oxygen-carrying protein in red blood cells. Individuals who are homozygous for the sickle cell trait often cannot endure exercise. Individuals who are heterozygous for the trait can have sickle cell attacks under extreme conditions. Normal individuals (Hb Hb) have only normal hemoglobin. Homozygous sickle cell individuals (Hb Hb') have only sickle cell hemoglobin. Heterozygous individuals (Hbs Hb) have both normal hemoglobin and sickle cell hemoglobin. Jerry Smith collapsed while running a race for his track team. A doctor said that he had a sickle cell attack. Genetic tests were run on several family members. The test results are shown below. An X indicates that form of hemoglobin in red blood cells. PROBLEM How can you determine the genotypes of people in a family? TABLE 1. FAMILY PHENOTYPES Normal Hemoglobin Subject Jerry Smith Jerry's brother Jerry's younger sister Jerry's youngest sister…arrow_forwardCan you check if A is correct and please help answer the following questions?arrow_forward
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