Provided herein are mitochondrial-nuclear exchanged cells and animals comprising mitochondrial DNA (mtDNA) from one subject and nuclear DNA (nDNA) from a different subject. Methods for producing a mitochondrial-nuclear exchanged animal and animals made by the methods are provided. Also provided are methods of screening for agents useful for treating a disease or disorder using mitochondrial-nuclear exchanged animals or cells, tissues or organs thereof.

The disclosure relates to a method of reprogramming one or more somatic cells, e.g., partially differentiated or fully/terminally differentiated somatic cells, to a less differentiated state, e.g., a pluripotent or multipotent state. In further embodiments the invention also relates to reprogrammed somatic cells produced by methods of the invention, to uses of said cells, and to methods for identifying agents useful for reprogramming somatic cells.

Method for selecting mammalian cells having a genetically-desirable trait, the method comprising culturing an embryo in vitro, dividing the cells from the embryo into aliquots, subjecting the cells from at least one of the aliquots to a genetic analysis, and, based on the results of such analysis, selecting an aliquot of cells. Method for selecting mammalian cells having a genetically-desirable trait, the method comprising culturing an embryo in vitro, transferring the cultured embryo into a recipient female, collecting the embryo, dividing the cells from the embryo into aliquots, subjecting the cells from at least one of the aliquots to a genetic analysis, and, based on the results of such analysis, selecting an aliquot of cells. Method for selecting a mammalian embryo having a genetically-desirable trait, the method comprising removing one or more cells from each of a plurality of embryos, culturing the cells, subjecting the cultured cells to a genetic analysis, and, based on the results of such analysis, selecting an embryo.

Method for selecting mammalian cells having a genetically-desirable trait, the method comprising culturing an embryo in vitro, dividing the cells from the embryo into aliquots, subjecting the cells from at least one of the aliquots to a genetic analysis, and, based on the results of such analysis, selecting an aliquot of cells. Method for selecting mammalian cells having a genetically-desirable trait, the method comprising culturing an embryo in vitro, transferring the cultured embryo into a recipient female, collecting the embryo, dividing the cells from the embryo into aliquots, subjecting the cells from at least one of the aliquots to a genetic analysis, and, based on the results of such analysis, selecting an aliquot of cells. Method for selecting a mammalian embryo having a genetically-desirable trait, the method comprising removing one or more cells from each of a plurality of embryos, culturing the cells, subjecting the cultured cells to a genetic analysis, and, based on the results of such analysis, selecting an embryo.

Genetic tests, such as whole genome analysis (WGA), have been employed to identify genetically superior embryos. The disclosed methods extend in vitro culture time of embryos while awaiting results of genetic tests being performed on a portion of the same embryos. The disclosed methods also help expand the number of cells in each embryo before implantation in the recipient.

Genetic tests, such as whole genome analysis (WGA), have been employed to identify genetically superior embryos. The disclosed methods extend in vitro culture time of embryos while awaiting results of genetic tests being performed on a portion of the same embryos. The disclosed methods also help expand the number of cells in each embryo before implantation in the recipient.