Suppose that rat liver expresses a protein called Yorfavase. The enzyme is composed of 192 amino acid residues, and thus the coding region of the yfg gene consists of 576 bp. However, the rat genome database indicates that the yfg gene consists of 1440 bp.
Select which type of DNA does not contribute to the additional 864 bp found in the yfg gene.
A. 5'-end untranslated regulatory region.
B. centromeric DNA
C. DNA coding for a signal sequence
D. noncoding intron
E. promoter sequence