In sickle cell anemia change in the amino acid is

(A) valine instead of glutamic acid in the 6th position of beta chain# Molecular basis of Sickle cell hemoglobin:> In case of sickle cell disease, the hemoglobin (HbS) has two normal a chains and two abnormal b chains.> This is due to a difference in a single amino acid. In HbS, glutamate at 6th position b-chain of is replaced by valine.> This occurs due to a change (missense mutation) in the single nucleotide (thymine a adenine) of the b globin gene. This error causes the formation of altered codon (GUG in place of GAG) which leads to the incorporation of valine at the 6th position.