Abstract: The invention provides methods of modifying the level of expression or functional activity of factors such as enzymes or other catalytic proteins or structural proteins, alone or in concert, to modify the frequency of meiotic homologous recombination involving the exchange of genetic information between non-sister chromatids from homologous maternal and paternal chromosomes. The steps at which modulation may occur include: homologous chromosome pairing, double-strand break formation; resection; strand invasion; branch migration; and resolution. Methods of plant and animal breeding are also provided that utilize the modulation of meiotic homologous recombination.

Abstract: The invention provides methods and nucleic acid constructs that may be used to modify a nucleic acid of interest at a target locus within the genome of a host. In some aspects, the invention contemplates producing in vivo a gene targeting substrate (GTS), which may be comprised of both DNA and RNA components. The gene targeting substrate may comprise a gene targeting nucleotide sequence (GTNS), which is homologous to the target locus, but comprises a sequence modification compared to the target locus. The gene targeting substrate may be produced by reverse transcription of a gene targeting message RNA (gtmRNA). The gene targeting message RNA may be folded for self-priming for reverse transcription by a reverse transcriptase. The gene targeting message RNA may in turn be the product of transcription of a gene targeting construct (GTC) encoding the gene targeting message RNA.

Abstract: The invention provides methods of modifying the level of expression or functional activity of factors such as enzymes or other catalytic proteins or structural proteins, alone or in concert, to modify the frequency of meiotic homologous recombination involving the exchange of genetic information between non-sister chromatids from homologous maternal and paternal chromosomes. The steps at which modulation may occur include: homologous chromosome pairing, double-strand break formation; resection; strand invasion; branch migration; and resolution. Methods of plant and animal breeding are also provided that utilize the modulation of meiotic homologous recombination.

Abstract: The invention provides methods of modifying the level of expression or functional activity of factors such as enzymes or other catalytic proteins or structural proteins, alone or in concert, to modify the frequency of meiotic homologous recombination involving the exchange of genetic information between non-sister chromatids from homologous maternal and paternal chromosomes. The steps at which modulation may occur include: homologous chromosome pairing, double-strand break formation; resection; strand invasion; branch migration; and resolution. Methods of plant and animal breeding are also provided that utilize the modulation of meiotic homologous recombination.

Abstract: The present invention provides methods of modifying in vivo mutagenesis or homologous and homeologous recombination in a eukaryote. The method of modifying in vivo mutagenesis involves transforming a eukaryote with a nucleotide sequence capable of expressing a wild-type prokaryotic MutS, MutL, MutH, MutU, NLS-MutS, NLS-MutL, NLS-MutH, NLS-MutU protein, or a combination thereof, and expressing the protein. A method of modifying recombination between homologous chromosomes in an allopolyploid eukaryotic organism comprising, expressing a nucleotide sequence encoding prokaryotic NLS-MutS in combination with one or more than one of NLS-MutL, NLS-MutH, or NLS-MutU, within a germ cell of the allopolyploid eukaryotic organism is also disclosed.

Abstract: The present invention provides methods of modifying in vivo mutagenesis or homologous recombination in a eukaryote. The method of modifying in vivo mutagenesis involves transforming a eukaryote with a nucleotide sequence capable of expressing a wild-type prokaryotic MutS, MutL, MutH, MutU, NLS-MutS, NLS-MutL, NLS-MutH, NLS-MutU protein, or a combination thereof, and expressing the protein. A method of modifying recombination between homologous chromosomes in an allopolyploid eukaryotic organism comprising, expressing a nucleotide sequence encoding prokaryotic NLS-MutS in combination with one or more than one of NLS-MutL, NLS-MutH, NLS-MutU, within a germ cell of the allopolyploid eukaryotic organism is also disclosed.

Abstract: The present invention provides methods of modifying in vivo mutagenesis or homeologous recombination in a eukaryote. The method of modifying in vivo mutagenesis involves transforming a eukaryote with a nucleotide sequence capable of expressing a wild-type prokaryotic MutS, MutL, MutH, MutU, NLS-MutS, NLS-MutL, NLS-MutH, NLS-MutU protein, or a combination thereof, and expressing the protein. A method of modifying recombination between homeologous chromosomes in an allopolyploid eukaryotic organism comprising, expressing a nucleotide sequence encoding prokaryotic NLS-MutS in combination with one or more than one of NLS-MutL, NLS-MutH, NLS-MutU, within a germ cell of the allopolyploid eukaryotic organism is also disclosed.

Abstract: The invention provides methods and nucleic acid constructs that may be used to modify a nucleic acid of interest at a target locus within the genome of a host. In some aspects, the invention contemplates producing in vivo a gene targeting substrate (GTS), which may be comprised of both DNA and RNA components. The gene targeting substrate may comprise a gene targeting nucleotide sequence (GTNS), which is homologous to the target locus, but comprises a sequence modification compared to the target locus. The gene targeting substrate may be produced by reverse transcription of a gene targeting message RNA (gtmRNA). The gene targeting message RNA may be folded for self-priming for reverse transcription by a reverse transcriptase. The gene targeting message RNA may in turn be the product of transcription of a gene targeting construct (GTC) encoding the gene targeting message RNA.

Abstract: In one aspect of the invention, single stranded DNA binding proteins (SSB) may be used to modulate homologous recombination in mitosis or meiosis. method are provided for modulating homologous recombination comprising transforming a cell with a nucleic acid encoding a single stranded DNA binding protein; and, allowing the cell to undergo mitosis or meiosis. Similarly, methods are provided for modulating homologous recombination comprising transforming a cell with an inhibitor of expression of a dingle stranded DNA binding protein, such as an antisense or co-suppressive nucleic acid; and, allowing the cell to undergo mitosis or meiosis.

Abstract: In some embodiments, the invention provides gene targeting systems that renew or regenerate a gene targeting cassette by various mechanisms of DNA replication to enable repeated cycles of gene targeting substrate production in vivo. In some embodiments, successive rounds of gene targeting cassette replication may allow the accumulation of multiple molecules of gene targeting substrate per cell or nucleus, so that the presence of more gene targeting substrate may result in a higher frequency of gene targeting events to produce heritable changes in a target host sequence by processes such as nucleic acid recombination and/or repair.

Abstract: In one aspect of the invention, single stranded DNA binding proteins (SSB) may be used to modulate homologous recombination in mitosis or meiosis. Methods are provided for modulating homologous recombination comprising transforming a cell with a nucleic acid encoding a single stranded DNA binding protein; and, allowing the cell to undergo mitosis or meiosis. Similarly, methods are provided for modulating homologous recombination comprising transforming a cell with an inhibitor of expression of a single stranded DNA binding protein, such as an antisense or co-suppressive nucleic acid; and, allowing the cell to undergo mitosis or meiosis.

Abstract: The invention provides methods of modifying the level of expression or functional activity of factors such as enzymes or other catalytic proteins or structural proteins, alone or in concert, to modify the frequency of meiotic homologous recombination involving the exchange of genetic information between non-sister chromatids from homologous maternal and paternal chromosomes. The steps at which modulation may occur include: homologous chromosome pairing, double-strand break formation; resection; strand invasion; branch migration; and resolution. Methods of plant and animal breeding are also provided that utilize the modulation of meiotic homologous recombination.