Mutations
A mutation is an alteration in the DNA of a cell. There are several terms you need to be aware of.
| Mutation | Description |
|---|---|
| Missense mutation | With a missense mutation, the new nucleotide alters the codon so as to produce an altered amino acid in the protein product |
| Nonsense mutations | With a nonsense mutation, the new nucleotide changes a codon that specified an amino acid to one of the STOP codons (TAA, TAG, or TGA). Therefore, translation of the messenger RNA transcribed from this mutant gene will stop prematurely. The earlier in the gene that this occurs, the more truncated the protein product and the more likely that it will be unable to function |
| Point Mutation | A point mutation is a simple change in one base of the gene sequence |
| Frame-shift mutation | An insertion or deletion of a number of nucleotides that shifts the sequence resulting in a completely different translation than the original |
| Silent mutation | A mutation that codes for that same amino acid |
