A method of retrieving a subset of polynuceotide molecules from a mixture of polynucleotide molecules includes receiving a mixture of nucleotide sequences comprising one or more polynucleotide molecules, synthesizing one or more identifier (ID) regions onto the one or more polynucleotide molecules. The method also includes generating a bead-bound library of one or more beads comprising subsets of identical polynucleotide molecules. Each bead is identified by the ID Sequence of the associated Polynucleotide Sequence. The method further includes sequencing the one or more ID regions of each bead to generate ID Sequence information for each bead, combining the Polynucleotide Sequence information, the one or more ID Sequences, and coordinates of each bead to identify the Polynucleotide Sequence on the bead, and retrieving the bead with its associated Polynucleotide Sequence from the flow cell based on the absolute coordinate position of the bead.