What type of mutation changes a single nucleotide in the DNA?

A point mutation refers to a change in a single nucleotide in the DNA sequence. This alteration can occur in several ways, such as a substitution, where one nucleotide is replaced by another. The consequence of a point mutation might vary; it can lead to a silent mutation (which does not change the amino acid sequence), a missense mutation (which results in a different amino acid), or a nonsense mutation (which creates a premature stop codon).

Understanding this concept is fundamental in genetics, as point mutations can significantly impact protein function, leading to varied biological outcomes. In contrast, options that involve frameshift or chromosomal mutations pertain to larger segments of DNA or alterations that change the reading frame or structure of chromosomes, therefore not fitting the definition of a change at the single nucleotide level.