title: Spontaneous epigenetic variation in the Arabidopsis thaliana methylome.
abstract: Heritable epigenetic polymorphisms, such as differential cytosine methylation, can underlie phenotypic variation. Moreover, wild strains of the plant Arabidopsis thaliana differ in many epialleles, and these can influence the expression of nearby genes. However, to understand their role in evolution, it is imperative to ascertain the emergence rate and stability of epialleles, including those that are not due to structural variation. We have compared genome-wide DNA methylation among 10 A. thaliana lines, derived 30 generations ago from a common ancestor. Epimutations at individual positions were easily detected, and close to 30,000 cytosines in each strain were differentially methylated. In contrast, larger regions of contiguous methylation were much more stable, and the frequency of changes was in the same low range as that of DNA mutations. Like individual positions, the same regions were often affected by differential methylation in independent lines, with evidence for recurrent cycles of forward and reverse mutations. Transposable elements and short interfering RNAs have been causally linked to DNA methylation. In agreement, differentially methylated sites were farther from transposable elements and showed less association with short interfering RNA expression than invariant positions. The biased distribution and frequent reversion of epimutations have important implications for the potential contribution of sequence-independent epialleles to plant evolution.
authors: Department of Molecular Biology, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany.
authors: Claude
authors: C
authors: Becker
authors: Jörg
authors: J
authors: Hagmann
authors: Jonas
authors: J
authors: Müller
authors: Daniel
authors: D
authors: Koenig
authors: Oliver
authors: O
authors: Stegle
authors: Karsten
authors: K
authors: Borgwardt
authors: Detlef
authors: D
authors: Weigel
mesh_terms: D000483:Alleles; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism*; D005075:Biological Evolution; D003596:Cytosine / Q000378:metabolism; D019175:DNA Methylation; D044127:Epigenesis, Genetic / Q000235:genetics*; D057890:Epigenomics; D005786:Gene Expression Regulation; D014644:Genetic Variation; D018745:Genome, Plant / Q000235:genetics; D010641:Phenotype; D011110:Polymorphism, Genetic
chemical_list: D003596:Cytosine