Methods and compositions for isolating asymmetric nucleic acid complexes

A method for isolating nucleic acid templates comprising:

• providing nucleic acid templates that comprise a double-stranded insert region with hairpin adapters at both ends, wherein the nucleic acid templates comprise a mixture of symmetrically-primed nucleic acid templates and asymmetrically-primed nucleic acid templates, wherein each symmetrically-primed nucleic acid template comprises capture primers hybridized to both terminal hairpin adapters or synthesis primers hybridized to both terminal hairpin adapters, and wherein each asymmetrically-primed nucleic acid template comprises a capture primer hybridized to the hairpin adapter at one end and a synthesis primer hybridized to the hairpin adapter at the opposite end;
• immobilizing the capture-primer hybridized templates to a solid support through the capture primer;
• maintaining the immobilized templates and a nucleic acid polymerase having strand displacement activity under conditions that promote nucleic acid synthesis from the synthesis primer, thereby eluting asymmetrically-primed nucleic acid templates from the solid support;
• and
• collecting the templates eluted from the solid support by the strand displacement activity of the nucleic acid polymerase, thereby isolating asymmetrically-primed nucleic acid templates.