Extended Data Figure 3. Replication timing boundaries preserved among tissues are conserved during evolution.

a, Heat map of TTR overlap with positive (yellow) or negative (blue) slope. Replication timing (RT) boundaries were identified as clustered TTR endpoints (grey) above the 95th percentile (dashed line) of randomly resampled positions (black). b, Examples of constitutive boundaries (blue regions) and regulated boundaries (grey regions) highlighted. c, Spearman correlations between differences in chromatin feature enrichment and differences in RT in non-overlapping 200-kb windows. d, Percentage of boundaries preserved between the indicated number of human cell types. e, f, Distribution of boundary replication timing in mouse (e) and human (f) as a function of preservation level between cell types. g, Comparison of changes in replication timing versus various histone marks across a segment of mouse chromosome 6.