Search Results (2)

Epigenetic factors have been suggested as mediators of early-life nutrition to future health. Prior studies focused on breastfeeding effects on DNA methylation (DNAm), ignoring other feeding modes. In this analysis of the Isle of Wight birth cohort, feeding modes were categorized as exclusive breastfeeding (EBF), exclusive formula feeding (EFF), and mixed feeding based on whether the respective feeding mode lasted for at least 3 months. In addition, in the past, infant feeding modes were assessed using DNAm at one time point in childhood, not changes of DNAm. In this paper, methylation differences (delta DNAm) were calculated by subtracting residual methylation values at birth from age 10 years (adjusting for cell types and season of blood collection at both ages). These deltas were estimated for all methylation sites where cytosine was followed by guanine (cytosine guanine dinucleotide (CpG) sites). Then, we performed an epigenome-wide association study contrasting EBF, EFF, and mixed feeding with delta DNAm that represents changes in methylation from birth to 10 years. A total of 87 CpGs (EBF: 27 CpGs, EFF: 48 CpGs, mixed: 12 CpGs) were identified using separate linear regression models adjusting for confounders and multiple testing. The sum of all changes in methylation from birth to age 10 years was significantly lower in the EFF group. Correspondingly, the number of CpGs with a methylation decline was 4.7% higher reflecting 13,683 CpGs. Lower methylation related to exclusive formula feeding and its adverse potential for the child’s development needs future research to reduce adverse health effects. Full article

DNA methylation has been considered a stable epigenetic mark but may respond to fluctuating environments. However, it is unclear how they behave in natural environments. Here, we analyzed seasonal patterns of genome-wide DNA methylation in a single clone from a natural population of the perennial Arabidopsis halleri. The genome-wide pattern of DNA methylation was primarily stable, and most of the repetitive regions were methylated across the year. Although the proportion was small, we detected seasonally methylated cytosines (SeMCs) in the genome. SeMCs in the CHH context were detected predominantly at repetitive sequences in intergenic regions. In contrast, gene-body CG methylation (gbM) itself was generally stable across seasons, but the levels of gbM were positively associated with seasonal stability of RNA expression of the genes. These results suggest the existence of two distinct aspects of DNA methylation in natural environments: sources of epigenetic variation and epigenetic marks for stable gene expression. Full article