Here's how it works:
* Genetic code redundancy: The genetic code is degenerate, meaning multiple codons (three-nucleotide sequences) can code for the same amino acid. For example, both UCU and UCC code for the amino acid serine.
* Silent mutation: A silent mutation occurs when a single nucleotide change within a codon doesn't change the amino acid that the codon codes for. For example, changing UCU to UCC is a silent mutation because both codons still code for serine.
Why are they called "silent"?
Because they don't alter the amino acid sequence, silent mutations often don't have a noticeable effect on the protein's function. This is why they're called "silent". However, there are some instances where silent mutations can have subtle effects:
* mRNA stability: Silent mutations can affect the stability of the mRNA molecule, potentially altering protein production levels.
* Splicing: In some cases, silent mutations within an intron (non-coding region) can affect mRNA splicing, potentially leading to changes in the final protein sequence.
* Translation efficiency: Silent mutations can subtly influence the efficiency of translation, affecting protein production rates.
Overall, silent mutations are generally considered less impactful than other types of mutations, like missense or nonsense mutations, which directly alter the amino acid sequence of a protein. However, they can still have subtle effects on gene expression and protein function.