Definition

1. Noun:
   • (Genetics) A mutation due to an intramolecular reorganization of a gene: A point mutation is a change in a single nucleotide base pair within the DNA sequence of a gene. This type of mutation involves the substitution, insertion, or deletion of one nucleotide, which can alter the genetic code.

Usage Examples

• Noun:
  • A single point mutation in the hemoglobin gene can cause sickle cell anemia.
  • Researchers identified the specific point mutation responsible for the change in the protein's function.
  • Not every point mutation leads to a noticeable change in an organism's traits.

Advanced Usage

• "Silent point mutation": A substitution that does not change the amino acid encoded, often due to the redundancy of the genetic code.

  • A silent point mutation may have no effect on the resulting protein.

• "Nonsense point mutation": A substitution that changes an amino acid codon into a stop codon, leading to a truncated protein.

  • The disease is caused by a nonsense point mutation that halts protein synthesis prematurely.

• "Missense point mutation": A substitution that changes one amino acid in the protein to a different one.

  • A missense point mutation can sometimes severely impair a protein's activity.

Variants and Related Words

• Gene mutation (n): A broader term for any heritable change in the DNA sequence of a gene.
• Single nucleotide polymorphism (SNP) (n): A common type of genetic variation involving a single nucleotide difference at a specific position in the genome; many SNPs are a form of .

Synonyms

• Base-pair substitution: Specifically refers to a where one nucleotide pair is replaced by another.
• Single-site mutation: Emphasizes that the change occurs at one specific location in the DNA.

Related Phrases

• To carry a point mutation: To possess a specific point mutation in one's genetic code.

  • The patient was found to carry the point mutation associated with the disorder.

• To induce a point mutation: To cause a point mutation to occur, often in a laboratory setting.

  • The chemical was used to induce a point mutation in the bacterial DNA.

Related Terminology

• Frameshift mutation: A different type of mutation caused by the insertion or deletion of nucleotides, shifting the reading frame of the gene. This contrasts with a substitution , which does not shift the frame.
• Mutagen (n): An agent, such as radiation or a chemical, that can cause mutations like .

Noun

1. (genetics) a mutation due to an intramolecular reorganization of a gene