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