DNA methylation variation in Arabidopsis has a genetic basis and appears to be involved in local adaptation
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ABSTRACT: We investigated DNA methylation variation in Swedish Arabidopsis thaliana accessions. We found that methylation of transposable elements is temperature sensitive and associated with genetic polymorphism in both cis and trans, whereas gene body methylation is associated with genetic polymorphism in trans. Additionally, complementary RNA-Seq data for the Arabidopsis accessions were used to correlate methylation changes with gene expression across environments.
Project description:We investigated DNA methylation variation in Swedish Arabidopsis thaliana accessions. We found that methylation of transposable elements is temperature sensitive and associated with genetic polymorphism in both cis and trans, whereas gene body methylation is associated with genetic polymorphism in trans. Additionally, complementary RNA-Seq data for the Arabidopsis accessions were used to correlate methylation changes with gene expression across environments. mRNA-sequencing (mRNA-Seq) of 160 Arabidopsis thaliana accessions grown at 10 C and 163 grown at 16 C. The source tissue for RNA collection was whole rosette at the 9-leaf stage.
Project description:Here we investigate DNA methylation variation in Swedish Arabidopsis thaliana accessions, demonstrating that methylation of transposable elements is temperature sensitive and associated with genetic polymorphism in both cis and trans, whereas gene body methylation is highly correlated with climate of origin and associated with genetic polymorphism in trans that shows evidence of local adaptation. While genome-wide surveys of naturally occurring DNA methylation have been published previously, the degree of genetic control revealed here is unprecedented. Furthermore, the observation that DNA methylation is associated with climate, and is apparently adaptively important, is completely novel. Bisulfite sequencing of 152 Swedish Arabidobsis accessions grown at 10 C and 121 grown at 16 C
Project description:Here we investigate DNA methylation variation in Swedish Arabidopsis thaliana accessions, demonstrating that methylation of transposable elements is temperature sensitive and associated with genetic polymorphism in both cis and trans, whereas gene body methylation is highly correlated with climate of origin and associated with genetic polymorphism in trans that shows evidence of local adaptation. While genome-wide surveys of naturally occurring DNA methylation have been published previously, the degree of genetic control revealed here is unprecedented. Furthermore, the observation that DNA methylation is associated with climate, and is apparently adaptively important, is completely novel.
Project description:DNA methylation is one of the important epigenetic marks conserved across both plants and animals. Recent work in Arabidopsis thaliana has demonstrated the existence of large geographic variation in DNA methylation, which must reflect genetic differences and/or an epigenetic memory of local environments. Here we investigate the cause of these differences in a genetic cross between a southern Swedish line with low DNA methylation and a northern Swedish line with high DNA methylation, carried out at two different temperatures. Using bisulfite-sequencing data with nucleotide-level resolution on hundreds of individuals, we find genetic and environmental factors regulating DNA methylation variation.
Project description:The heterotic hybrid offspring of Arabidopsis accessions C24 and Landsberg erecta have altered methylomes. Changes occur most frequently at loci where parental methylation levels are different. There are context-specific biases in the non-additive methylation patterns with mCG generally increased and mCHH decreased relative to the parents. These changes are a result of two main mechanisms, Trans Chromosomal Methylation (TCM) and Trans Chromosomal deMethylation (TCdM), where the methylation level of one parental allele alters to resemble that of the other parent. Regions of altered methylation are enriched around genic regions and are often correlated with changes in siRNA levels. We identified examples of genes with altered expression likely to be due to methylation changes and suggest that in crosses between the C24 and Ler accessions, epigenetic controls can be important in the generation of altered transcription levels which may contribute to the increased biomass of the hybrids.
Project description:The heterotic hybrid offspring of Arabidopsis accessions C24 and Landsberg erecta have altered methylomes. Changes occur most frequently at loci where parental methylation levels are different. There are context-specific biases in the non-additive methylation patterns with mCG generally increased and mCHH decreased relative to the parents. These changes are a result of two main mechanisms, Trans Chromosomal Methylation (TCM) and Trans Chromosomal deMethylation (TCdM), where the methylation level of one parental allele alters to resemble that of the other parent. Regions of altered methylation are enriched around genic regions and are often correlated with changes in siRNA levels. We identified examples of genes with altered expression likely to be due to methylation changes and suggest that in crosses between the C24 and Ler accessions, epigenetic controls can be important in the generation of altered transcription levels which may contribute to the increased biomass of the hybrids. C24, Ler, and C24 x Ler
Project description:Gene expression of Col, Van and reciprocal hybrids using double-stranded cDNA followed by bioprime random labeling, and hybridization to AtTILE1 forward array. Study on gene expression polymorphism between arabidopsis thaliana accessions Col-0 and Van-0. Study on the inheritance of gene expression in reciprocal hybrids. Keywords: cDNA hybridization
Project description:Natural epigenetic variation provides a source for the generation of phenotypic diversity, but to understand its contribution to phenotypic diversity, its interaction with genetic variation requires further investigation. Here, we report population-wide DNA sequencing of genomes, transcriptomes, and methylomes of wild Arabidopsis thaliana accessions. Single cytosine methylation polymorphisms are unlinked to genotype. However, the rate of linkage disequilibrium decay amongst differentially methylated regions targeted by RNA-directed DNA methylation is similar to the rate for single nucleotide polymorphisms. Association analyses of these RNA-directed DNA methylation regions with genetic variants identified 2,372 methylQTL, which revealed the first population estimate of genetically dependent methylation variation. Analysis of invariably methylated transposons and genes across this population indicates that loci targeted by RNA-directed DNA methylation are epigenetically reactivated during male gametogenesis, which facilitates their silencing across generations. RNA-seq from naturally-occurring Arabidopsis accessions
Project description:Expression level polymorphisms (ELPs) often result in cis-acting expression quantitative trait loci (cis-eQTL), which are important QTL and association mapping tools and account significantly for phenotypic variability. Generally, it is assumed that such stably heritable ELP represent regulatory element polymorphisms in the respective genes. However, comprehensive genome-wide analyses linking expression level, regulatory sequence and gene structure variation are missing, preventing definite verification of this assumption. Here we analyzed heritability of ELP observed between Arabidopsis thaliana accessions Eil-0 and Lc-0 by comparing genotyped recombinant inbred lines (RIL) to their parents in microarray analyses. Keywords: expression level polymorphism, Arabidopsis thaliana accessions, recombinant inbred lines
Project description:Affymetrix single nucleotide polymorphism (SNP) array data were used to study genes that underlie human adaptation to climatic stress, with a focus on genetic changes that lead to long-term cold tolerance. Siberia provides the best opportunity to investigate the genetic mechanisms of cold resistance because of the long-term ancestry of indigenous populations in some of the coldest climates on earth. While much of northern Europe was under ice throughout the last glacial period, Siberia remained relatively ice free, and archaeological evidence suggests that people inhabited this region for more than 40,000 years. We gathered SNP data from ~200 individuals from 15 indigenous Siberian populations that inhabit a range of arctic climates and compare their patterns of genetic variation with those from other world populations from warmer climates.Particular attention is paid to regions containing genes that have been previously implicated in cold adaptation or that function in known pathways connected to energy metabolism or cold adapted phenotypes (e.g., those involved in basal metabolic rate and brown adipose tissue function).