| a genetic association study of the mu opioid receptor and severe opioid dependence. | twin, family and adoption studies have suggested that vulnerability to opioid dependence may be a partially inherited trait (cadoret et al., 1986; merikangas et al., 1998; tsuang et al., 1998, 2001). studies using animal models also support a role for genetic factors in opioid dependence, and point to a locus of major effect on mouse chromosome 10 (berrettini et al., 1994; alexander et al., 1996), which harbors the mu opioid receptor gene (mor1) (kozak et al., 1994). the gene encoding the human ... | 2003 | 12960749 |