on some of these culled genes, none will be hub nodes. We also note that the sample sizes used in the current study were sufficient to produce networks of high quality (Langfelder and Horvath, 2008). The selection of the High and Low ethanol preference lines from HS-CC founders has been described elsewhere (Colville et al., 2017). The HS-CC was derived from eight mouse strains, including three wild-derived strains; the genetic diversity captured is ∼90% of that available in M. musculus (Roberts et al., 2007). The preference lines were bred using a short-term selective breeding protocol (Belknap et al., 1997; Metten et al., 2014) that minimizes the stochastic fixation of alleles unrelated to the phenotype of interest, here 2-bottle choice ethanol preference. From the perspective of ethanol preference and consumption, the HS-CC are of interest in that ∼25% of the animals show a preference for ethanol; this differs from a <5% preference found in our HS/NPT mice (unpublished observation) that were derived from eight laboratory mouse strains (Hitzemann et al., 2014).
