Abstract: The invention relates to genetic manipulations of eukaryotic organisms, with recombinant DNA comprising RNA virus derived sequences for protecting such organisms against RNA viruses or enabling inducible or tissue-specific production of foreign proteins/peptides or RNAs. One embodiment of the recombinant DNA according to the invention comprises recombinant DNA, comprising two, 12-1250 base pair long, inverted repeat nucleotide sequences with therebetween at least one nucleotide sequence which is derived from RNA virus which for its replication is dependent upon a viral RNA/RNA polymerase, said RNA virus derived sequence comprising at least cis elements for replication but no gene that codes for viral RNA/RNA polymerase and no gene that codes for viral coat protein. The invention also relates to eukaryotic or prokaryotic cells or organisms which incorporate the recombinant DNA according to the invention.

Abstract: The invention relates to genetic manipulations of eukaryotic organisms, with recombinant DNA comprising RNA virus derived sequences for protecting such organisms against RNA viruses or enabling inducible or tissue-specific production of foreign proteins/peptides or RNAs. One embodiment of the recombinant DNA according to the invention comprises recombinant DNA, comprising two, 12-250 base pair long, inverted repeat nucleotide sequences with therebetween at least one nucleotide sequence which is derived from RNA virus which for its replication is dependent upon a viral RNA/RNA polymerase, said RNA virus derived sequence comprising at least cis elements for replication but no gene that codes for viral RNA/RNA polymerase and no gene that codes for viral coat protein. The invention also relates to eukaryotic or prokaryotic cells or organisms which incorporate the recombinant DNA according to the invention.

Abstract: The invention relates to a process for transforming cells and to a recombinant DNA molecule for use therein. Said recombinant DNA molecule is a multifunctional linker comprising a DNA sequence which is homologous to a part of the receptor genome, an operator sequence and either a sequence which allows replication in a microorganism or a sequence which allows for integrative recombination in a vector. Preferably, said multifunctional linker also contains a gene whose expression can be detected in a microorganism, a gene whose expression can be detected in the receptor, a sequence which promotes recombination, and/or a hairpin structure at one or both ends. The transformation process uses donor DNA coupled to the multifunctional linker and allows for early success followed by further characterization of the donor DNA and its phenotypic impact.