Fig. 7.

Evolutionary conservation of TADs and gene expression constraint. To assess whether TAD conservation is associated with interspecies variation in gene expression, we compared the standard deviation (SD) of gene expression between TADs showing high (ranks 9–11), intermediate (ranks 4–8) and low (ranks 1–3) levels of conservation. Genes from highly conserved TADs show significantly less interspecies variation in expression compared with genes from less conserved TADs (the Wilcoxon rank sum test [high vs. low: $P=0.016$, high vs. medium $P=0.026$]).