Figure 3
From: Concordant and discordant DNA methylation signatures of aging in human blood and brain
Hierarchical clustering of samples by PCs revealed distinct cluster patterns. Sample IDs indicate sample tissue, color tags (bottom) are mapped to the age of the individual (red: young, green: old). (A) Clustering of samples from a selection of all CpG sites with > 4σ variance across samples. The first cluster separated blood from brain. Inside the brain region, samples clustered by individual instead of tissue. (B) Clustering of samples from a selection of CpG sites with ≷ ± 4σ projections in PC1. (C) Clustering of samples from a selection of CpG sites with ≷ ± 4σ projections in PC4, an age-related PC. PC, principal component; BA10, Broadmann area 10; BA20, Broadmann area 20, BA7, Broadmann area 7; WB, whole blood.