point mutation (gene mutation) A change in the nucleotide sequence of the DNA within a gene; a gene in which such a change has occurred is known as a mutant gene or allele (see mutation). The DNA sequence can be altered in several ways; for example by insertion, substitution, deletion, and inversion. Point mutations result in a misreading of the genetic code during the translation phase of protein synthesis and usually change the order of amino acids making up a protein, which may or may not affect the function of that protein. See also intergenic suppressor; missense mutation. Compare chromosome mutation; single nucleotide polymorphism.

point mutation A mutation that can be mapped to one specific locus: it is caused by the substitution of one nucleotide for another. A point mutation may also be caused by deletion and inversion.

point mutation A mutation that occurs at only one nucleotide site. The term is often used synonymously with substitution.

point mutation A mutation that can be mapped to one specific locus. It is caused by the substitution of one nucleotide for another.