Repeat enrichment patterns in human CD4+ T cells. (a) To normalize read counts in the absence of input sequencing data, the enrichment values were estimated relative to other marks using distributions of enrichment coefficients observed for each repeat type (see Materials and methods). The plot shows enrichment coefficients for various chromatin marks for the HSAT6 repeat. H3K9me3 and H4K20me3 deviate from the nominal levels exhibited by most of the marks in a statistically significant way. (b) Similar to Figure 3a, the repeat types were clustered according to their combined enrichment estimates across measured chromatin marks. Part of the plot containing no enrichment clusters is omitted (see Figure S9 in Additional file 1 for a complete plot). Repeat families over-abundant within major clusters are labeled on the plot. (c) Enlarged view of the tRNA-dominated cluster located at the top of the plot shown in (b).