This invention provides nucleic acid affinity matrices that bear a large
number of different nucleic acid affinity ligands allowing the
simultaneous selection and removal of a large number of preselected
nucleic acids from the sample. Methods of producing such affinity matrices
are also provided. In general the methods involve the steps of a)
providing a nucleic acid amplification template array comprising a surface
to which are attached at least 50 oligonucleotides having different
nucleic acid sequences, and wherein each different oligonucleotide is
localized in a predetermined region of said surface, the density of said
oligonucleotides is greater than about 60 different oligonucleotides per 1
cm.sup.2, and all of said different oligonucleotides have an identical
terminal 3' nucleic acid sequence and an identical terminal 5' nucleic
acid sequence. b) amplifying said multiplicity of oligonucleotides to
provide a pool of amplified nucleic acids; and c) attaching the pool of
nucleic acids to a solid support.
