▁the ▁function ▁has ▁been ▁determined ▁and ▁comp ounds ▁that ▁mod ulate ▁the ▁function ▁of ▁those ▁targets ▁( lig ands ▁in ▁the ▁case ▁of ▁re cept ors , ▁in hib itors ▁of ▁en zym es , ▁or ▁block ers ▁of ▁ion ▁channels ) ▁ ▁have ▁been ▁identified . ▁Other ▁members ▁of ▁the ▁target ▁family ▁may ▁have ▁unknown ▁function ▁with ▁no ▁known ▁lig ands ▁and ▁hence ▁are ▁class ified ▁as ▁or phan ▁re cept ors . ▁By ▁ident ifying ▁screen ing ▁hits ▁that ▁mod ulate ▁the ▁activity ▁of ▁the ▁less ▁well ▁character ized ▁members ▁of ▁the ▁target ▁family , ▁the ▁function ▁of ▁these ▁novel ▁targets ▁can ▁be ▁el uc id ated . ▁ ▁Furthermore , ▁the ▁hits ▁for ▁these ▁targets ▁can ▁be ▁used ▁as ▁a ▁starting ▁point ▁for ▁drug ▁discovery . ▁The ▁completion ▁of ▁the ▁human ▁gen ome ▁project ▁has ▁provided ▁an ▁abund ance ▁of ▁potential ▁targets ▁for ▁th era pe ut ic ▁inter vention . ▁ ▁Chem ogen om ics ▁st riv es ▁to ▁study ▁the ▁intersection ▁of ▁all ▁possible ▁dru gs ▁on ▁all ▁of ▁these ▁potential ▁targets . ▁ ▁A ▁common ▁method ▁to ▁construct ▁a ▁target ed ▁chemical ▁library ▁is ▁to ▁include ▁known ▁lig ands ▁of ▁at ▁least ▁one ▁and ▁prefer ably ▁several ▁members ▁of ▁the ▁target ▁family . ▁Since ▁a ▁portion ▁of ▁lig ands ▁that ▁were ▁designed ▁and ▁synth es ized ▁to ▁bind ▁to ▁one ▁family ▁member ▁will ▁also ▁bind ▁to ▁additional ▁family ▁members , ▁the ▁comp ounds ▁contained ▁in ▁a ▁target ed ▁chemical ▁library ▁should ▁collect ively ▁bind ▁to ▁a ▁high