Annotation of the DW genes showed significant enrichment in genes associated with cell–cell adhesion (Table S6) and neuron part. Genes in the former category included 18 protocadherin related genes; only one of these, Pdch15, was detected as DE between preferring and non-preferring animals by Mulligan et al. (2006). Genes associated with neuron part included a number of glutamate receptor subunits (Gria3, Grid2, Grik2, Grin2a, Grm1, Grm3, Grm4 and Grm7), voltage-gated potassium channels (Kcna4, Kcnab1, Kcnb1, Kcnb2 and Kcnd2) and kinesin-related genes (Kif1a, Kif1b, Kif5a, Kif5b and Kif5c). Of the genes associated with neuron part, 27 were also detected as DE by Mulligan et al. (2006); these included Grid2, Mapk1, Mapk8ip3, Pde4b, Psen1, Shank3 and Snap25. The DW genes were significantly enriched in five coexpression modules: brown (P < 3 × 10−14), greenyellow (P < 1 × 10−18), lightcyan (P < 3 × 10−10), pink (P < 3 × 10−4) and yellow (P < 2 × 10−7). Annotations for the greenyellow and pink module are discussed above. The brown module (Table S3) was enriched in annotations associated with synaptic function, including
