The two largest ethanol-responsive networks, ErGeN1 and ErGeN3, shared a common regulator on the proximal end of Chr 7, between 15.52 and 36.48 Mb (Table 2). Examination of eQTL for all members of these networks revealed a complicated pattern of association, in which the trans-band could be subdivided into several groups based on peak eQTL locations that clustered between 16.3 and 35.04 Mb (Figure S6). Peak linkage of genes from ErGeN3, however, was limited to a narrow region between 30.1 and 30.2 Mb, at the distal edge of the support interval. This locus represents the common regulatory hot-spot shared by these two networks and harbors the two most highly ranked candidate regulators of the Chr 7 trans-band: Scn1b, a voltage gated sodium channel subunit and Aplp1, amyloid beta precursor-like protein (Table 3). Both genes were significantly ethanol-responsive, highly connected hub nodes in ErGeN1 and associated with cis eQTL in the saline data. Unlike Aplp1, The ethanol response of Scn1b was at least partially regulated by a local polymorphism, as evidenced by its suggestive cis eQTL in the S-score data. Both
