The fi chain of adult hemoglobin is composed of 146 amino acids of a known sequence. In comparing the normal fi chain with the fi chain in sickle -cell hemoglobin, what alteration is one likely to find?
A) valine instead of glutamic acid in the sixth position B) frameshift substitutions C) trinucleotide repeats D) glutamic acid replacing valine in the first position E) extensive amino acid substitutions