Correlations between receptor coding variation, clade, chromosomal location and function. (A) The accumulation of non-synonymous SNPs does not differ between VR sub-families within either lab-derived or wild-derived strains (Mean + SEM. Two-way ANOVA, variance in receptor subfamily F2,28 = 0.312, P = 0.734, variance in strain F1,28 = 17.01, P = 0.001. Bonferroni post hoc tests of all combinations within strains, ns = P > 0.05). (B,C) Non-synonymous SNP distribution within lab-derived strains displays correlations with V2R organisation byprincipal component (PC) analysis. The two most important PCs (accounting for 72% of the variation in the data) are plotted against each other for all V2R genes. Examples of V2R genes within select cladesare highlighted, having different directional clustering across the PC axes: (B) V2RB and V2RC (red and blue) differ from V2RA5 (purple). (C) Differences in grouping is also observed within a clade that has two arrays of receptors located on different chromosomes (V2RA8 on chromosome 7, red and on chromosome 17, blue). (D) V2Rs that detect sympatric cues in domesticus are more variable in other Mus species or subspecies, than those that detect predator or conspecific cues. Mainly domesticus-derived strains were pooled and those strains from another Mus species or subspecies were pooled. The functional classification of each V2R gene is as described  (Mean + SEM. Two-way ANOVA, variance in function F2,28 = 17.29, P < 0.0001, variance in strain F1,28 = 27.8, P = 0.0001. Bonferroni post hoc tests of all combinations of functional class within strainpools, ns = P > 0.05, ** = P < 0.01, *** = P < 0.001).