AASDHPPT and tetrasomy 12p: The presence of free-standing ACPs is not uncommon within PKS gene clusters (Piel, 2010; Cantu et al., 2012) including trans-AT PKS clusters such as those for mupirocin (El-Sayed et al., 2003; Gurney and Thomas, 2011) and difficidin (Chen et al., 2006).