Synonymous substitution

A synonymous substitution refers to a specific type of mutation in DNA or RNA where a change in the nucleotide sequence does not alter the amino acid sequence of the resulting protein. This occurs because multiple codons can code for the same amino acid due to the redundancy of the genetic code. For example, consider the amino acid leucine, which can be encoded by several codons: UUA, UUG, CUU, CUC, CUA, and CUG.