DNA methylation is a chromatin modification that contributes to epigenetic regulation of gene expression. The inheritance patterns and trans-generational stability of 962 differentially methylated regions (DMRs) were assessed in a panel of 71 near-isogenic lines (NILs) derived from maize (Zea mays) inbred lines B73 and Mo17. The majority of DMRs exhibit inheritance patterns that would be expected for local (cis) inheritance of DNA methylation variation such that DNA methylation level was coupled to local genotype. There are few examples of DNA methylation that exhibit trans-acting control or paramutation-like patterns. The cis-inherited DMRs provide an opportunity to study the stability of inheritance for DNA methylation variation. There was very little evidence for alterations of DNA methylation levels at these DMRs during the generations of the NIL population development. DNA methylation level was associated with local genotypes in nearly all of the .30,000 potential cases of inheritance. The majority of the DMRs were not associated with small RNAs. Together, our results suggest that a significant portion of DNA methylation variation in maize exhibits locally (cis) inherited patterns, is highly stable, and does not require active programming by small RNAs for maintenance. DNA methylation may contribute to heritable epigenetic information in many eukaryotic genomes. In this study, we have documented the inheritance patterns and trans-generational stability for nearly 1000 DNA methylation variants in a segregating maize population. At most loci studied, the DNA methylation differences are locally inherited and are not influenced by the other allele or other genomic regions. The inheritance of DNA methylation levels across generations is quite robust with almost no examples of unstable inheritance, suggesting that DNA methylation differences can be quite stably inherited, even in segregating populations.
MANY organisms exhibit abundant phenotypic diversity within a species. This observed diversity is often attributed to genetic variation, but there is a large part of this diversity that cannot be explained by genetic polymorphisms alone (Manolio et al. 2009). It has been proposed that epigenetic variation could be one component of this missing heritability (Petronis 2010). DNA methylation is a well-studied contributor to epigenetic information in many eukaryotes. In plants, DNA methylation occurs in three sequence contexts, CG, CHG, and CHH (where H = A, T, or C). It is widely accepted that de novo establishment of DNA methylation is often guided by small RNA (RNA-directed DNA methylation, RdDM), while maintenance of DNA methylation is performed by different methyltransferases, namely MET1 (METHYL-TRANSFERASE 1) for CG methylation, CMT3 (CHROMOME-THYLASE 3), and DRM1/2 (DOMAINS REARRANGED METHYLTRANSFERASE 1 and 2) for non-CG methylation (CHG and CHH) (Chan et al. 2005). Variation in DNA methylation profiles has been observed in many species (Vaughn et al. 2007;Eichten et al. 2011bEichten et al. , 2013Re...