In general, recombinant techniques involve isolating {HEAD ~ the genes} responsible for coding growth factor, cloning the gene in suitable vectors and cell types, modifying {TAIL ~ the gene} if necessary to encode a desired variant, and expressing the gene in order to produce the growth factor protein product 
In general , recombinant techniques involve isolating { HEAD ~ the genes } responsible for coding growth factor , cloning the gene in suitable vectors and cell types , modifying { TAIL ~ the gene } if necessary to encode a desired variant , and expressing the gene in order to produce the growth factor protein product
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH