A frame-shift mutation where a nucleotide is deleted from the genetic material

• A. Insertion mutation
• B. Substitution mutation
• C. Point mutation
• D. Deletion mutation

Answer: (D)

Removing a nucleotide shifts the reading frame of the genetic code. Because codons are read in groups of three bases, deleting one base changes every downstream codon, altering which amino acids are added and often producing a nonfunctional protein. This kind of change is called a deletion mutation, and when it involves removing just one nucleotide it typically creates a frameshift. An insertion would add a base and can also cause a frameshift, while substitution replaces a base without shifting the frame, and a point mutation usually refers to a single-base substitution rather than deletion. So the description fits a deletion mutation.