{HEAD ~ The amplified nucleic acid fragment} preferably will encode {TAIL ~ a portion} of a polypeptide  
{ HEAD ~ The amplified nucleic acid fragment } preferably will encode { TAIL ~ a portion } of a polypeptide
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH