Fig. 2

a Heatmap shows a clustering analysis of the 31 CpG sites that were significantly differentially methylated between Hainan centenarians and healthy controls. Columns: individual samples (1–12 are centenarians; 13–24 are healthy controls). Rows: CpG sites. Blue color: low methylation level; yellow color: high methylation level. b Volcano plot: each dot on the plot is a single CpG site. Horizontal axis: Beta. Difference (Δβ); vertical axis: -log10 of p value. Colour coding is based on the Δβ. Thick vertical lines highlight Δβ of − 0.2 and 0.2, while a thick horizontal line represents a p-value of 0.01. The red dots and blue dots represent hypermethylated sites and hypomethylated sites in centenarians, respectively