Abstract: This invention concerns recombinant RNA molecules comprising a recognition sequence for the binding of an RNA-directed RNA polymerase, a sequence for the initiation of product strand synthesis and a heterologous sequence of interest inserted at a specific site in the internal region of the recombinant molecule. Such recombinant RNA molecules are capable of serving as a template for the synthesis of complementary single-stranded molecules by RNA-directed RNA polymerase. The product molecules so formed are also capable of serving as a template for the synthesis of additional copies of the original recombinant RNA molecule. In a preferred embodiment of the invention Q.beta. replicase is used as the RNA-directed RNA polymerase.

Abstract: For the detection of nucleic acids of definite sequence by hybridisation with a complementary nucleic acid probe which contains bound via a chemical bonding at least one hapten as labelling one uses, as hapten, a steroid which is bound via a bridge of at least 4 atoms length to at least one position of the nucleic acid probe which does not participate in hydrogen bridge formation and detects the hybridised probe via an in turn labelled anti-hapten antibody.