Patent ID: 8071311

Claim:
A method for isothermally amplifying a target nucleic acid comprising a) hybridizing a first RNA-DNA composite primer to the target nucleic acid; b) extending said first RNA-DNA composite primer using a polymerase; c) using RNase H, degrading a 5â€² portion of said first RNA-DNA composite primer to leave a first product comprising a single-stranded 3â€² overhang, wherein said 5â€² portion forms a hybridized portion of a nucleic acid duplex prior to said degrading; d) hybridizing a second RNA-DNA composite primer to the single-stranded 3â€² overhang of the first product, wherein the second RNA-DNA composite primer comprises the same sequence as a 3â€² portion of the first RNA-DNA composite primer that is not degraded in step (c); e) displacing the extended first RNA-DNA composite primer by extending said second primer using a polymerase, such that said extended first primer is released from said target nucleic acid; f) hybridizing a third RNA-DNA composite primer with said extended first RNA-DNA composite primer; and g) repeating steps (b)-(e), wherein said first RNA-DNA composite primer is replaced by said third RNA-DNA composite primer to produce a second product, said RNA-DNA composite second RNA-DNA composite primer is replaced by a fourth RNA-DNA composite primer to displace an extended third RNA-DNA composite primer, and said fourth RNA-DNA composite primer comprises the same sequence as a 3â€² portion of said third RNA-DNA composite primer that is not degraded in step (c); whereby said target nucleic acid is amplified to produce amplified products.