Point mutation
A single nucleotide base change in the DNA. A point mutation may consist of the loss of a nucleotide, the insertion of an additional nucleotide, or the substitution of one nucleotide for another. The first point mutation discovered in humans involved the substitution of one nucleotide for another. It was in sickle hemoglobin, the molecular basis for sickle cell trait and sickle cell anemia. The mutation results in an amino acid change from glutamic acid to valine, from normal adult hemoglobin (hemoglobin A) to sickle hemoglobin (hemoglobin S).
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point mutation n a gene mutation involving the substitution, addition, or deletion of a single nucleotide base
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a mutation resulting from a change in a single base pair in the DNA molecule, caused by the substitution of one nucleotide for another. See also chromosomal m. and genomic m.
Medical dictionary.
2011.