Figure 8. The 3-base-pair deletion in cystic fibrosis. The mutation Involves the deletion of CTT in the tenth exon of the gene. The sequence on the left is from a healthy individual and the sequence on the right is from a patient with cystic fibrosis. This 3-base-pair deletion results in the loss of phenylalanine from the protein. (Reprinted with permission: Watson J, Gilman M, Witkowski J, Zoller M: Recombinant DNA. New York, W. H. Freeman and Co., 1992, p. 530.)