PCA plot of cross-correlations between Comt genotype (ComtB2i) and inflammatory and neuropathic pain assays. (A) Absence of the ComtB2i haplotype (and absence of the B2 SINE in the 3′ UTR) is shown to be closely related to spontaneous inflammatory nociception (ACAA, AAMS, BV, CAP, FEarly, FLate), but not to mechanical sensitivity (VF) and not to mechanical (TC) or thermal nociception (HP, HT, TF, TW−15, TW47.5, TW49). The proportion of total variance accounted for is 0.65. (B) ComtB2i haplotype is not strongly related to sensitivity in any of the neuropathic pain assays examined, represented graphically with a shorter vector for Comt genotype; however, presence of the ComtB2i haplotype, -(ComtB2i), is consistently mildly related to the neuropathic cold hypersensitivity assays (PACACET, PACCOLD, SNIACET) (0.14 ≤ rs ≤ 0.28 with absence of ComtB2i) (Table 2). The proportion of total variance accounted for is 0.50. Font color reference is as in Fig. 2 legend.