Point mutations
Substitutions result in a change that only affect one codon. This is known as a point mutation. The resulting mutation can be one of three types:
| Missense | Nonsense | Splice-site |
| change the codon so that a different amino acid is produced | change the codon from an amino acid to a stop codon | affect the boundaries between exons and introns (splice sites) |
| may result in the shape of the protein changing so that it cannot carry out its function | results in a shorter protein being produced | can prevent splicing at that site |
| some changes in amino acid may not have any significant effect | shortened protein is generally non-functional or its function is affected | a very different protein is made due to the post transcriptional processing as some introns may be included or some exons removed |
| Missense | change the codon so that a different amino acid is produced |
|---|---|
| Nonsense | change the codon from an amino acid to a stop codon |
| Splice-site | affect the boundaries between exons and introns (splice sites) |
| Missense | may result in the shape of the protein changing so that it cannot carry out its function |
|---|---|
| Nonsense | results in a shorter protein being produced |
| Splice-site | can prevent splicing at that site |
| Missense | some changes in amino acid may not have any significant effect |
|---|---|
| Nonsense | shortened protein is generally non-functional or its function is affected |
| Splice-site | a very different protein is made due to the post transcriptional processing as some introns may be included or some exons removed |