The field of neuroimaging genetics provides a promising approach for elucidating mechanisms of genetic susceptibility in relation to brain structure and function (Tan et al. 2008). Also, the field of epigenetics has highlighted the presence of heritable changes in gene expression that occurs independently of alterations in primary DNA sequence (Kiefer, 2007). Brain development is under epigenetic control, and alterations in brain structure and subsequent function may be contributed to differential promoter DNA methylation patterns, histone changes, and chromosomal interactions in the absence of allelic variations. Epigenetic mechanisms may account for one-third to one-half of known genetic alterations, and they may provide an understanding of the molecular underpinnings of long-term changes in the structure and function of the brain (Weinhold 2006). It is likely that the changes in the neural structures of the externalizing and internalizing behavioral pathways to AUD are modulated by a variety of genetic mechanisms. Accommodating the influences of genetic variation and epigenetic events will be important in future models of AUD.
