<P>PROBLEM TO BE SOLVED: To provide a human artificial chromosome which is genetically transmissible to the next generation with high efficiency, and to provide the method for using the same. <P>SOLUTION: A human antibody-producing mouse carrying (a) a non-rearranged human antibody heavy chain gene locus, (b) a non-rearranged human antibody κ light chain gene locus and (c) a non-rearranged human antibody λ light chain gene locus is provided, wherein at least one of (a), (b) and (c) is carried on a human-origin chromosome fragment, at least one of (a), (b) and (c) is inserted in a mouse chromosome, at least both alleles of endogenous heavy chain and both alleles of endogenous κ light chain are inactivated and the human antibody heavy chain, the human κ light chain and the human λ light chain are exhibited in serum of the mouse. <P>COPYRIGHT: (C)2005,JPO&NCIPI 
ARTIFICIAL HUMAN CHROMOSOME CONTAINING HUMAN ANTIBODY lambda LIGHT CHAIN GENE AND NON-HUMAN ANIMAL CONTAINING THE ARTIFICIAL HUMAN CHROMOSOME GENETICALLY TRANSMISSIBLE TO OFFSPRING