point mutation
Học thuậtThân thiện
Definition
- Noun:
- (Genetics) A mutation due to an intramolecular reorganization of a gene: A
point mutationis 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 mutationin the hemoglobin gene can cause sickle cell anemia. - Researchers identified the specific
point mutationresponsible for the change in the protein's function. - Not every
point mutationleads 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 mutationmay 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 mutationthat halts protein synthesis prematurely.
"Missense point mutation": A substitution that changes one amino acid in the protein to a different one.
- A missense
point mutationcan 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 mutationin one's genetic code.- The patient was found to carry the
point mutationassociated with the disorder.
To induce a point mutation: To cause a
point mutationto occur, often in a laboratory setting.- The chemical was used to induce a
point mutationin 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
- (genetics) a mutation due to an intramolecular reorganization of a gene