- Not to be confused with the evolutionary concept of a transitional fossil.
In genetics, a transition is a point mutation that changes a purine nucleotide to another purine (A <-> G) or a pyrimidine nucleotide to another pyrimidine (C <-> T). Approximately two out of three single nucleotide polymorphisms (SNPs) are transitions.[1]
Transitions can be caused by oxidative deamination and tautomerization.[2] Although there are twice as many possible transversions, transitions appear more often in genomes, possibly due to the molecular mechanisms that generate them[3].
5-Methylcytosine is more prone to transition than unmethylated cytosine, due to spontaneous deamination. This mechanism is important because it dictates the rarity of CpG islands.
See also
References
- ^ Rates of transition and transversion in coding sequences since human-rodent divergence
- ^ Mutations & Mutagenesis
- ^ Genomewide comparison of DNA sequences between humans and chimpanzees
External links
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