Transition (genetics) - Misplaced Pages

DNA mutation that exchanges two nucleotides For other uses, see Transition.

Transition, in genetics and molecular biology, refers to 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.

Transitions can be caused by oxidative deamination and tautomerization. Although there are twice as many possible transversions, transitions appear more often in genomes, possibly due to the molecular mechanisms that generate them. Transitions are more likely to be synonymous substitutions than transversions, as one observes in the codon table.

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.

References

Collins DW, Jukes TH (April 1994). "Rates of transition and transversion in coding sequences since the human-rodent divergence". Genomics. 20 (3): 386–96. doi:10.1006/geno.1994.1192. PMID 8034311.
Ebersberger I, Metzler D, Schwarz C, Pääbo S (June 2002). "Genomewide comparison of DNA sequences between humans and chimpanzees". Am. J. Hum. Genet. 70 (6): 1490–7. doi:10.1086/340787. PMC 379137. PMID 11992255.
Mezhzherin, S. V.; Tereshchenko, V. O. (2023-06-01). "Genetic Divergence and Evolutionary Transition/Transversion Rate Bias in the Control Region of Mitochondrial DNA of Palearctic Mice (Murinae)". Cytology and Genetics. 57 (3): 213–220. doi:10.3103/S0095452723030076. ISSN 1934-9440. S2CID 259191096.

Mechanisms of mutation

Mutation with respect to structure

Point mutation	Nonsense mutation Missense mutation Conservative mutation Silent mutation Frameshift mutation Dynamic mutation
Large-scale mutation	Chromosomal translocations Chromosomal inversions

Mutation with respect to overall fitness

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