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Molecular Basis of Heredity: Part 3. Genetic Variation

Author(s): Raye L. Alford, PhD

The Molecular Basis of DNA Sequence Variations (II)

Nonsense mutations are substitution mutations that result in the substitution of a stop codon into a protein at a position where an amino acid would normally occur. Nonsense mutations result in the premature truncation of a protein. If the nonsense mutation occurs at the beginning of the gene, it may result in a complete loss of the functional capabilities provided by a protein derived from the mutated gene. If it occurs near the middle or end of the gene, it may result in the production of a protein missing only some of its functional capabilities.