AP BIOLOGY

Detailed explanation-1: -Mutations caused by insertion or deletion of nitrogenous bases in the DNA sequence leads to the most damage to DNA since it completely changes the reading frame for the process of protein synthesis. Insertion or deletion that results in frameshift mutation are considered as the most damaging mutation.

Detailed explanation-2: -Because an insertion or deletion results in a frame-shift that changes the reading of subsequent codons and, therefore, alters the entire amino acid sequence that follows the mutation, insertions and deletions are usually more harmful than a substitution in which only a single amino acid is altered.

Detailed explanation-3: -A frameshift variant occurs when there is an addition or loss of nucleotides that shifts the grouping and changes the code for all downstream amino acids. The resulting protein is usually nonfunctional. Insertions, deletions, and duplications can all be frameshift variants.

Detailed explanation-4: -Frameshift mutations are among the most deleterious changes to the coding sequence of a protein. They are extremely likely to lead to large-scale changes to polypeptide length and chemical composition, resulting in a non-functional protein that often disrupts the biochemical processes of a cell.