A method of identifying RNA ligands which bind to a target molecule by treating a first pool of RNA ligands that collectively bind more than one target under conditions effective to reduce the concentration or eliminate the presence of one or more predominate target-binding RNA ligands from the first pool of RNA ligands; amplifying the RNA ligands in the treated first pool, thereby forming a second pool of RNA ligands that is enriched in one or more non-predominate target-binding RNA ligands of the first pool but not the one or more predominate target-binding RNA ligands thereof; and identifying one or more predominate target-binding RNA ligands that are present in the second pool at a higher concentration than other target-binding RNA ligands. Oligonucleotides and kits which can be used in practicing the present invention are also disclosed, as are aptamers that bind to a heat shock factor protein and their use.