- AUG is the most common start codon and codes for the amino acid methionine. It is also known as the "universal start codon" because it is used by all organisms.
- GUG and UUG are less common start codons, but they can also code for methionine. They are sometimes used when AUG is not available, such as when it is mutated or deleted.
When a ribosome binds to an mRNA, it scans the sequence until it finds a start codon. Once a start codon is found, the ribosome begins to translate the mRNA into protein.
