What type of mutations can affect an entire gene and lead to a malfunction?

Insertions and deletions are types of mutations that can significantly impact an entire gene, often leading to a malfunction. These mutations involve the addition or removal of one or more nucleotides in the DNA sequence. When such changes occur within a gene, they can disrupt the reading frame of the genetic code, a situation known as frameshift mutation.

A frameshift can alter the entire sequence of amino acids that follow, potentially resulting in a completely nonfunctional protein. This can lead to serious consequences in biological processes, as the protein's structure and function are drastically changed.

In contrast, point mutations, which involve the substitution of a single nucleotide, might only affect one amino acid in a protein, and depending on the specific mutation, could be silent or not lead to functional loss. Silent mutations do not alter the protein's structure at all, while back mutations restore the original nucleotide sequence, thereby reinstating the normal function of the gene. Therefore, insertions and deletions stand out as mutations that can comprehensively affect gene function.