The remainder of this review describes our studies of reelin-related events in the hippocampus and periphery of rats using a well characterized animal model of depression (Kalynchuk et al., 2004; Gregus et al., 2005; Johnson et al., 2006; Marks et al., 2009; Sterner and Kalynchuk, 2010), as well as our examination of peripheral biomarkers in depression patients (Rivera-Baltanás et al., 2012, 2014, 2015). This evidence concerns the gene RELN and major depressive disorder.