Table 1 Principal component (PC) analysis of epigenetic marks illustrates associations between chromatin state and coding sequence evolution
C. floridanus (Ant)D. melanogaster (Fly)
PC1 (39.4%)PC2 (20.0%)PC3 (16.6%)PC1 (55.2%)PC2 (14.8%)PC3 (11.7%)
Eigenvectors
 DNA methylation0.45−0.33−0.04NDNDND
 H3K4me30.460.360.030.460.21−0.12
 H3K27ac0.450.220.000.370.41−0.16
 H3K36me30.420.040.140.40−0.330.40
 H3K4me10.21−0.390.450.37−0.220.36
 H3K27me30.020.180.77−0.400.14−0.25
 H3K9ac−0.040.72−0.030.410.34−0.41
 H3K9me3−0.400.070.43−0.170.710.67
Correlation coefficients of gene expression metrics with PCs
 RNA Pol II0.60****0.07**0.19****0.78****0.25****−0.08***
 Expression level0.59****0.01−0.040.55****0.020.00
 Tissue specificityNDNDND−0.60****−0.05*−0.01
Correlation coefficients of sequence substitution metrics with PCs
 dS0.21****−0.11****−0.11****0.20****0.05*0.10****
 dN−0.03−0.15****0.06**−0.05*−0.05*0.07***
 dN/dS−0.11****−0.12****0.11****−0.13****−0.07***0.04
  • PCs explaining less than 10% variation are not shown. *P < 0.05, **P < 10–2, ***P < 10–3, ****P < 10–4; ND, no data.