Patent ID: 8795971

Claim:
A method for producing at least one nucleic acid cluster having an identifiable center, comprising: (a) generating, on a solid support, at least one immobilized nucleic acid complement of at least one nucleic acid template; (b) carrying out a first set of amplification cycles to amplify the at least one nucleic acid template and the at least one nucleic acid complement in the presence of a nucleoside analog to obtain a region comprising immobilized copies of the at least one nucleic acid template and of the at least one nucleic acid complement, the immobilized copies comprising the nucleoside analog; (c) carrying out a second set of amplification cycles in the absence of the nucleoside analog to obtain on the solid support at least one nucleic acid cluster, wherein each cluster comprises (i) a substantially central location comprising the at least one nucleic acid template and the at least one nucleic acid complement comprising the nucleoside analog, and (ii) a surrounding region comprising one or more immobilized copies of the at least one nucleic acid template and of the at least one nucleic acid complement lacking the nucleoside analog; and (d) selectively removing nucleic acids in the substantially central location while leaving the nucleic acids in the surrounding region, thereby producing at least one nucleic acid cluster having an identifiable center.