Patent ID: 8445238

Claim:
A method for forming a 3′ hairpin structure, comprising; a) contacting a sample suspected of containing a target nucleic acid with a snap-back primer and a reverse primer, wherein said snap-back primer comprises: i) a 3′ region configured to hybridize to said target nucleic acid such that it can be extended by a polymerase, and ii) a 5′ region that is configured to not hybridize to said target nucleic when said 3′ region of said snap-back primer is hybridized to said target nucleic acid; and wherein said contacting is under conditions such that: i) said 3′ region of said snap-back primer hybridizes to said target nucleic acid and is extended to generate a first amplification product, and ii) said reverse primer hybridizes to said first amplification product and is extended to generate a second amplification product, wherein said second amplification product comprises a 3′ snap-back portion capable of hybridizing to a non-adjacent portion of said second amplification product, and b) treating said sample under conditions such that said second amplification product is separated from said first amplification product, and said second amplification product forms a 3′ hairpin structure, wherein said 3′ hairpin structure comprises: i) said 3′ snap-back portion hybridized to said non-adjacent portion; and ii) a 3′ terminal portion not hybridized to said second amplification product.