Rates of forward epimutations (i.e., stochastic gains of methylation) & backward epimutations (i.e., stochastic loss of methylation) in MA [mutation accumulation]-lines

Range forward epimutations ~2.56×10^−4: backward epimutations ~6.3×10^−4 epimutation/CG site/haploid genome/generation
Organism Thale cress Arabidopsis thaliana
Reference Vidalis A, Živković D, Wardenaar R, Roquis D, Tellier A, Johannes F. Methylome evolution in plants. Genome Biol. 2016 Dec 20 17(1):264. doi: 10.1186/s13059-016-1127-5. p.6 right column top paragraphPubMed ID27998290
Primary Source [78] Van der Graaf A, Wardenaar R, Neumann DA, Taudt A, Shaw RG, Jansen RC, et al. Rate, spectrum, and evolutionary dynamics of spontaneous epimutations. Proc Natl Acad Sci U S A. 2015 112: 6676–81. DOI: 10.1073/pnas.1424254112PubMed ID25964364
Method Estimates in MA-lines
Comments P.6 right column top paragraph: "Estimates in MA-lines indicate that the rate of forward epimutations (i.e., stochastic gains of methylation) is about 2.56×10^−4 per CG site per haploid genome per generation, while the rate of backward epimutations (i.e., stochastic loss of methylation) is about 6.3×10^−4 [primary source]. Hence, methylation loss is globally about 2.5 times as likely as methylation gain. The asymmetry in these rates has immediate consequences for understanding GMLs (Genome-wide Methylation Levels-a measure of the percentage of all cytosines that are methylated) in A. thaliana: it implies that about 30% of all CG dinucleotides should be methylated at equilibrium and 70% unmethylated, provided that evolutionary forces such as selection and gene conversion are negligible."
Entered by Uri M
ID 113098