A naturally occurring centromere derived from a mouse chromosome; a long arm fragment derived from a mouse chromosome, which is produced by deleting a distal long arm from a mouse chromosome long arm which is located adjacent to centromere; a mouse artificial chromosome vector characterized by containing a telomere sequence and capable of being retained stably in a mammalian cell and an individual tissue; a cell or a non-human animal which carries the vector; and use of the cell or the non-human animal.