(A) Number of unique DBDPs in 1kG (Phase 3), ESP 6500, or ExAC v0.2 individuals. (B) Histograms of unique DBDPs per individual in either homozygous or heterozygous states. (C) Number of Mendelian mutations, and nsSNPs found in ExAC, across all homeodomain TFs annotated by their position and type of DNA contact associated with each position. “I”, “II, “III” refer to α-helices; III is the DNA-recognition helix. Adjacent bar graphs depict mean number of variants for each position type; enrichment (*) or depletion (**) relative to non-DNA-contacting residues (P < 0.05, permutation test), error bars = 1 standard error of the mean, N = 332 Mendelian mutations, 1,300 nsSNPs, and 11 base-contacting, 12 phosphate-backbone-contacting, 5 neighboring-DNA-contacting, and 30 non-DNA-contacting positions. (D) Allele types assayed by PBMs.