In sickle cell anaemia glutamic acid is replaced by valine Which one of the following triplets codes for valine ?

Options

A. G G G
B. A A G
C. G A A
D. G U G

Answer

D

Explanation

Sickle-cell anaemia is an autosome linked recessive trait. This disease is controlled by a single pair of alled `Hb^(A) and Hb^(S)` only the homozygous individuals for `hb^(S)` , i.e., `Hb^(S)Hb^(S)` shows the diseased phenotype. The heterzygous individuals are carriers `(Hb^(A)Hb^(S)).` Due to point multation, glutamic acid (Glu) is replaced by valine (Val) at sixth position of `beta`-chain of haemoglobin molecule. This subsituation occurs due to the signal base substitution of the beta globin gene from GAG (Glu) to GUG (Val).
Whereas, the other codes GGG, AAG, GAA do not codes for valine.