Abstract: This invention relates to a process for amplifying and detecting any desired specific nucleic acid sequence that exists in a nucleic acid or mixture thereof. The process comprises treating single strand RNA or separated complementary strands of DNA target with a molar excess of oligonucleotide complement pairs in which these oligonucleotide complement pairs have sequences complementary to the target, under hybridizing conditions. In one embodiment, the oligonucleotide complement pairs may have a gap of one or more bases which may be repaired (filled) by enzymes. The oligonucleotide complement pairs are joined together, forming joined, oligonucleotide product. The target/joined product hybrid nucleic acids are then denatured to single strands again, at which point both the target and the joined products can form hybrids with new oligonucleotide complement pairs. The steps of the reaction may be carried out stepwise or simultaneously and can be repeated as often as desired.

Abstract: A method for amplifying a signal during the detection of target nucleic acid molecules utilizes a primary oligonucleotide probe that binds to a bridging nucleic acid molecule. The bridging molecule hybridizes to a first developer nucleic acid molecule. Each first developer molecule comprises: (a) a first branch having a sequence of at least two different nucleotides and at least six total nucleotides complementary to a sequence of a first branch of a second developer molecule; (b) a second branch comprising a sequence of at least two different nucleotides and at least six total nucleotides complementary to a sequence of a second branch of the second developer molecule; and (c) a detectable label.