In HbS, the human hemoglobin found in individuals with sickle-cell anemia, glutamic acid at position 6 in the beta chain is replaced by valine. Q.) Show that one of the glutamic acid codons can be converted to a valine codon by a single substitution mutation (i.e., by changing one letter in one codon).
In HbS, the human hemoglobin found in individuals with sickle-cell anemia, glutamic acid at position 6 in the beta chain is replaced by valine.
Q.) Show that one of the glutamic acid codons can be converted to a valine codon by a single substitution mutation (i.e., by changing one letter in one codon).
Sickle cell anemia is a genetic condition that results from a mutation in the gene that codes for the chain of hemoglobin. The mutation in the genetic code causes the amino acid glutamic acid to be substituted with valine at a specific location. This change causes the hemoglobin to lose its typical globular shape and adapt a different shape. This causes red blood cells to lose their concave shape and change into a sickle-like shape.
Sickle cell disease is inherited in an autosomal recessive manner, i.e., two copies of the mutated allele must be present for the symptoms to be expressed. Complications that can arise as a result include anemia, fatigue, hemolytic crisis, lack of oxygen to tissues (which could lead to ischaemia), and spleen damage.
Each amino acid is encoded by a group of three nucleotides known as a codon. A change in the DNA sequence may hence affect the amino acid being encoded.
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