The order of bases in mRNA that codes for the first eight amino acids in the $\beta$-polypeptide of adult haemoglobin is: GUG-CAC-CUG-ACU-CCU-GAG-GAG-AAG. For haemoglobin C, which causes haemolytic anaemia, the order is: GUG-CAC-CUG-ACU-CCU-AAG-GAG-AAG. The coding for seven of the amino acids is given. Which alteration takes place in the amino acid sequence of adult haemoglobin to produce haemoglobin C?
- AHistidine is changed to leucine.
- BProline is changed to threonine.
- CGlutamic acid is changed to lysine.
- DLeucine is changed to phenylalanine.