Question

In a protein-coding region of DNA, a mutation that replaces a single nucleotide, but does not change the resulting amino acid, is likely to be:

Answer 1

A mutation in a protein-coding region of DNA that replaces a single nucleotide, but does not change the resulting amino acid is likely to be a silent mutation. Such a mutation is effectively 'silent' due to the degeneracy of the genetic code that allows multiple codons to code for the same amino acid.

Step-by-step explanation:

In a protein-coding region of DNA, a mutation that replaces a single nucleotide, but does not change the resulting amino acid, is likely to be a silent mutation. This is because silent mutations result in no change in the amino acid and hence the protein sequence remains unaltered. This type of mutation is 'silent' as it has no observable effect on the organism's phenotype.

An important concept to understand here is 'degeneracy' of the genetic code, which means that multiple codons can code for the same amino acid. So even when a nucleotide is mutated or replaced, as long as it results in coding for the same amino acid, the change is essentially silent. For example, the codons UCU, UCC, UCA, UCG, AGU, and AGC all code for the amino acid Serine. So, if a mutation changes UCU to UCA, the resulting amino acid in the protein will still be Serine hence rendering the mutation silent.

Learn more about Silent Mutation