Question: In humans, sickle cell disease is a hereditary disease that affects the protein hemoglobin in red blood cells and is caused by a mutation in DNA that changes and mRNA codon from GAG to GUG. As a result, the amino acid _____ in one of the polypetide chans of hemoglobin is replaced with the amino acid _____, which is nonpolar and causes hemoglobin to clump and red blood cells to form a sickle shape. aparatic acid; valine, glutamic acid; glycine, glutamic acid; valine, aspartic acid; glycine. Need Assignment Help?