Alternatively, {TAIL ~ a nucleotide sequence} encoding {HEAD ~ the desired growth factor protein product} may be chemically synthesized 
Alternatively , { TAIL ~ a nucleotide sequence } encoding { HEAD ~ the desired growth factor protein product } may be chemically synthesized
OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH