Genetics majors only please Half the population of a country is homozygous reces
ID: 86835 • Letter: G
Question
Genetics majors only pleaseHalf the population of a country is homozygous recessive for a deletion in a glycophorin C gene, producing a shortened protein. This protein is normally on the surface of red blood cells, and functions in maintaining the shape of the cell. Other proteins also perform this function and being homozygous recessive for this protein does not effect health. However this protein acts as a receptor for the malaria parasite to enter the cells, and these homozygous people are resistant to malaria. Is this a case of balanced polymorphism? Explain Genetics majors only please
Half the population of a country is homozygous recessive for a deletion in a glycophorin C gene, producing a shortened protein. This protein is normally on the surface of red blood cells, and functions in maintaining the shape of the cell. Other proteins also perform this function and being homozygous recessive for this protein does not effect health. However this protein acts as a receptor for the malaria parasite to enter the cells, and these homozygous people are resistant to malaria. Is this a case of balanced polymorphism? Explain
Half the population of a country is homozygous recessive for a deletion in a glycophorin C gene, producing a shortened protein. This protein is normally on the surface of red blood cells, and functions in maintaining the shape of the cell. Other proteins also perform this function and being homozygous recessive for this protein does not effect health. However this protein acts as a receptor for the malaria parasite to enter the cells, and these homozygous people are resistant to malaria. Is this a case of balanced polymorphism? Explain
Explanation / Answer
The genetic selective scenario in which a heterozygote for two alleles of a gene has an advantage over either of the homozygous state is called " balanced polymorphism".In human sickle cell disease is associated with a balanced polymorphism.Individuals withthis disease are homozygous for a mutant allele of the beta globin gene,donated HBBs,and they suffer from a severe form of anemia in which the hemoglobin molecules crystalline in the blood.the crystallization causes the red blood cells to assume a charecterstic sickle shape.
The answer is that there is moderate selection against homozygous that carry the wild type alleleHBB1.these homozygous are less fit then the HBBSHBBA heterozygotes because they are more suceptible to infection by the paresites that cause malaria,a fitness reducing disease that is widespread in regions where the frequency of HBBs allele is high.the selective inferiority of the HBBSHBBS and HBBAHBBA homozygotes compared to the heterozygotes create a balanced polymorphism in which both alleles of the beta globin gene are maintained in the population .so,the protein acts as are receptor for the malaria parasite to enter the cells.but these homozygous people are resistant to malaria.nd its a case of balanced polymorphism.
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