Fig. 1: Evolutionary conservation of gene expression and chromatin structure between mouse and chicken embryonic hearts despite divergent CREs.
a, Reptilian and mammalian lineages convergently evolved fully separated four-chambered hearts. E10.5 and HH22 represent equivalent stages of heart formation. b, Conservation of global gene expression (log2-transformed fold change (FC) of heart-expressed versus limb-expressed genes) between mouse (E10.5) and chicken (HH22). c, ATAC-seq peaks (E10.5 heart) were mostly alignable (LiftOver (minMatch = 0.1)) to chicken in coding but not noncoding regions. d, Syntenic regions at the Hand2/HAND2 locus shows conserved 3D chromatin structure and histone modifications relative to the target gene despite different genomic size. Coverage track unit, counts per million. Dashed triangle indicates conserved topological domain structure, blue circles and dashed rectangle show specific contacts to conserved enhancers. Blue ticks indicate conserved sequences and green or purple ticks indicate predicted promoters or enhancers. e, Signal enrichment (± 3kb) of histone modifications at heart promoters (pro.) and enhancers (enh.) (E10.5, HH22), centered on ATAC-seq summits. f, Fraction of alignable elements identified in e with the chicken or mouse genome (LiftOver (minMatch = 0.1)). Align., alignment; CPM, counts per million.
