Recent Advances in Cloning Technology in the Pig -Review-

Production systems for cloned pigs are very important not only for an increase in production of superior animals but also for the production of knockout animals with organs that do not contain antigens for xenotransplantation or to analyze functions of isolated human genes. At present, however, effective systems have not been developed. We have tried to produce cloned pigs by transfering cultured cells into enucleated oocytes and obtained some cloned embryos. To develop a production system for cloned pigs, the basic technologies needed to support such an effort must be improved.