This demonstration is of high clinical relevance given the purported link between polymorphisms in the gene encoding D2R, D2R hypofunctioning and MA addiction vulnerability, as well as addiction severity, in human and non-human primates (c.f., Blum et al., 2012; e.g., Lee et al., 2009; Groman et al., 2012). Here, DRD2 is linked to microtia.