PKNOX2 belongs to the three-amino-acid loop extension (TALE) homeobox family (82). It is a highly conserved nuclear transcription regulator indicated by its structure and sub-cellular localization. PKNOX2 was expressed in rodent brain and has been identified as one of the cis-regulated genes for alcohol addiction in mice (83). MREG encodes for elanoregulin, and may function in membrane fusion and regulate the biogenesis of disk membranes of photoreceptor rod cells. In humans, mutations in the GPD1L gene have been reported to cause Brugada syndrome 2, which is a progressive disorder of myocardial conduction (84). Interestingly, this gene has received support for the phenotype `alcohol stimulated activity' in the mouse (85), as it is located in the QTL Etact2 on mouse chromosome 9. CMTM8 belongs to the chemokine-like factor gene superfamily, a novel family that is similar to the chemokine and the transmembrane 4 superfamilies. It is widely expressed in many tissues, but the exact function of the encoded protein is unknown. MAP3K9 on Chr14 encodes for a mixed lineage kinase including the serine/threonine kinase that acts as an essential component of
