Nucleotide Transition Abnormality

**Semantic type:** Cell or Molecular Dysfunction

**Definition:** A point mutation that involves the substitution of a pyrimidine base for a different pyrimidine base or substitution of a purine base for a different purine base. Nucleotide transitions do not change the purine-pyrimidine orientation of a DNA sequence. A nucleotide transition abnormality may be heritable or occur somatically.

**Synonyms:** - Transition - Transition Mutation