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Frameshift mutations are a kind of genetic mutation where the insertion or deletion of nucleotides disrupts the reading frame of a gene. This shift can have significant effects because the reading frame determines how codons (groups of three nucleotides) are read during the translation process to make proteins. When the reading frame is altered, it can result in an entirely different translation from the original. Here are the two main types of frameshift mutations:

First, we have insertion mutations. This type occurs when additional nucleotides are inserted into the DNA sequence.
Second, there are deletion mutations, where nucleotides are removed from the DNA sequence.

Let's explore each type in more detail.

Insertion mutations happen when extra nucleotides are added into the DNA sequence. This addition shifts the reading frame from the point of insertion onward, potentially altering every subsequent amino acid in the sequence.

Consider this simple example: if the original DNA sequence is `ATG GGC TAA` (where each triplet is a codon), and we insert an extra 'A' after the first codon, the sequence becomes `ATG AGG CTA A`. The reading frame shifts, and the triplets are read differently. Instead of the original codons, we now have a new set of codons after the insertion.

This change can lead to the production of nonfunctional proteins or cause diseases, as the entire sequence downstream of the insertion is altered. Therefore, insertion mutations can be especially harmful if they occur in critical regions of a gene.

Deletion mutations are the opposite of insertion mutations. They occur when one or more nucleotides are removed from the DNA sequence. This removal shifts the reading frame, similarly disrupting the entire sequence downstream of the deletion.

For example, if our original sequence is `ATG GGC TAA`, and we delete one nucleotide, say 'G', from the second codon, we get `ATG GCT AA`. The reading frame changes, and the resultant codons are different from the original ones.

Like insertion mutations, deletion mutations can have a dramatic effect on protein production. They often lead to truncated, nonfunctional proteins or completely different proteins, leading to malfunction and sometimes causing genetic disorders.

In summary, frameshift mutations, whether by insertion or deletion, can significantly alter the genetic code and result in severe consequences for an organism.