How does base insertion or deletion impact the genetic code?

Base insertion or deletion has a significant impact on the genetic code due to the way codons are read during protein synthesis. The genetic code is read in triplets of nucleotides, known as codons. When a base is either inserted or deleted from the sequence, it shifts the reading frame, affecting all subsequent codons downstream of the mutation. This is known as a frameshift mutation.

As a result of this shift, the entire sequence of codons changes after the point of insertion or deletion, leading to the production of a completely different set of amino acids from that point onward. This can drastically alter the structure and function of the resulting protein, potentially leading to significant biological consequences.

In contrast, a base alteration may only affect a single amino acid, and while duplications can occur in some contexts, they typically arise from replication errors rather than direct insertion or deletion. A lack of significant effect is also incorrect, as frameshift mutations often lead to dysfunctional proteins or diseases. Thus, the key consequence of base insertion or deletion is indeed the alteration of the reading frame, which is critical for understanding how such mutations can influence genetic expression and function.