{HEAD ~ The method} also allows for the identification of nucleic acids that have facilitating {TAIL ~ activities} as measured by their ability to facilitate formation of a covalent bond between the nucleic acid, including its associated functional unit, and its target 
{ HEAD ~ The method } also allows for the identification of nucleic acids that have facilitating { TAIL ~ activities } as measured by their ability to facilitate formation of a covalent bond between the nucleic acid , including its associated functional unit , and its target
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH 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 OTH OTH OTH OTH OTH