행위

Mutation

Jin (토론 | 기여)님의 2016년 7월 8일 (금) 18:22 판

돌연변이(Mutation, 변이)은 nucleotide sequence의 변화를 말한다.

분류

  • Point mutations((silent, missense, and nonsense)
    • Transition: purine to purine (eg, A to G) or pyrimidine to pyrimidine (eg, C to T).
    • Transversion: purine to pyrimidine (eg, A to T) or pyrimidine to purine (eg, C to G).
  • Silent mutation: Nucleotide substitution but codes for same(synonymous) amino acid; often base change

in 3rd position of codon (tRNA wobble).

  • Missense mutation: Nucleotide substitution->changed amino acid (called conservative if new amino acid is similar in chemical structure)
  • Nonsense mutation: Nucleotide substitution -> early stop codon. -> usually nonfunctional protein
  • Frameshift mutation: Deletion or insertion of a number of nucleotides not divisible by 3 ->misreading of all nucleotides downstream. Protein may be shorter or longer, and its function may be disrupted or altered.
  • 기타
    • Splice site mutation -> retained intron in the mRNA protein with impaired or altered function.
      • Rare cause of cancers, dementia, epilepsy, some types of β-thalassemia.