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