Which mutation is characterized by the replacement of one nucleotide with another?

The mutation characterized by the replacement of one nucleotide with another is substitution. In this type of mutation, a single base pair in the DNA sequence is changed, which can alter the corresponding codon and potentially lead to a change in the amino acid sequence during protein synthesis. This can have varying effects on the organism, ranging from no significant impact (silent mutations) to changes that might affect the function of proteins (missense mutations) or create a premature stop codon (nonsense mutations).

In contrast, insertion refers to the addition of one or more nucleotide bases into the DNA sequence, which can shift the reading frame during translation. Deletion involves the removal of one or more nucleotides, also potentially causing a frameshift. Translocation is the rearrangement of parts between non-homologous chromosomes and does not involve simple nucleotide replacement. This understanding highlights the specific and significant nature of substitution mutations within the broader context of genetic variability and evolution.