The present invention includes methods for integrating a modifying
polynucleotide into a target polynucleotide in a cell, or instance, a
fish cell or a mouse cell, and methods for making chimeric animals,
heterozygous animals, and homozygous animals that are chimeric,
heterozygous, or homozygous, respectively, for a modifying polynucleotide
integrated into a target polynucleotide. The present invention also
includes vectors and methods of using the vectors for integrating a
modifying polynucleotide into a target polynucleotide in a cell, for
instance, a fish cell or a mouse cell.