AP BIOLOGY

Detailed explanation-1: -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-2: -An insertion or deletion involving a number of base pairs that is not a multiple of three, which consequently disrupts the triplet reading frame of a DNA sequence.

Detailed explanation-3: -Thus, if a mutation, for example, an insertion or a deletion of the nucleotide, occurs, this could result in the alteration of the reading frame. It completely changes the amino acid sequence. Such mutations are known as frameshift mutation (also called reading frame mutation, reading frame shift, or framing error).

Detailed explanation-4: -Frameshift mutations are deletions or additions of 1, 2, or 4 nucleotides that change the ribosome reading frame and cause premature termination of translation at a new nonsense or chain termination codon (TAA, TAG, and TGA).

Detailed explanation-5: -Deletions or insertions of a base (or bases) into the genome cause a shift in the reading frame and are thus called frameshift mutations; they result in a grossly different translation of the message beyond the site of the mutation.