Abstract: The present invention provides transgenic animals (e.g., transgenic porcine animals), organs, tissues, and cells derived from the transgenic animals that are particularly useful for xenotransplantation therapies. In particular, the present invention provides transgenic porcine animals, as well as organs, tissues and cells derived from the transgenic porcine animals, which lack any expression of a functional alpha 1,3 galactosyltransferase (GTKO) gene and comprise at least six transgenes under the control of at least three promoters within a single multi-gene expression vector, and further comprise at least four additional genetic modifications. Also provided are methods of making the transgenic animals (e.g., transgenic porcine animals), and methods of using the transgenic animals, organs, tissues, and cells derived from the transgenic animals for xenotransplantation therapies and treating a disease or condition.