What kind of mutation involves a change in a single DNA nucleotide?

A point mutation is characterized by a change in a single nucleotide within the DNA sequence. This alteration can occur in several ways: it might involve the substitution of one nucleotide for another, the addition of a nucleotide, or the deletion of a nucleotide. Such mutations can have varying effects on the resulting protein, depending on the nature of the change. If the change does not alter the amino acid sequence, it is referred to as a silent mutation; however, if the amino acid sequence does change, it can lead to a missense mutation or, in some cases, a nonsense mutation that results in a premature stop codon.

Understanding point mutations is essential because they can have significant implications for gene function and potentially lead to diseases if they disrupt normal cellular processes. This stands in contrast to chromosomal mutations, which involve larger segments of DNA and can affect multiple genes, and translocation mutations, which specifically refer to the movement of a chromosome segment to a new position, particularly within a non-homologous chromosome.