{HEAD ~ Yields} of virus like particles derived from {TAIL ~ those optimized HPV L1 genes} are high 
{ HEAD ~ Yields } of virus like particles derived from { TAIL ~ those optimized HPV L1 genes } are high
HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH