Disclosed is a method for producing a chimericnon-human animal, which comprises preparing a microcellcontaining a foreign chromosome or a fragment thereof andtransferring the foreign chromosome or fragment thereof intoa pluripotent cell by fusion with the microcell. Alsodisclosed are a chimeric non-human animal which can beproduced by the above method and its progeny； tissues andcells derived therefrom； and a method for using the same.Further disclosed are a pluripotent cell containing aforeign chromosome or a fragment thereof, a method forproducing the same, and a method for using the same.
