SELEX is an acronym for {HEAD ~ Systematic Evolution} of {TAIL ~ Ligands} by EXponential enrichment 
of
SELEX is an acronym for { HEAD ~ Systematic Evolution } of { TAIL ~ Ligands } by EXponential enrichment
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH