These may include, for example, chalcone synthase of petunia or {HEAD ~ polygalacturonase} of {TAIL ~ tomato}  
These may include , for example , chalcone synthase of petunia or { HEAD ~ polygalacturonase } of { TAIL ~ tomato }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH