Rabbits are widely used as experimental animals in various fields of research. However, unlike mice and rats, rabbits with a homologous genetic background are difficult to obtain, as few inbred strains have been established because of the fact that inbreeding decreases reproductive ability. Moreover, an embryonic stem (ES) cell line with germline chimeras has not been established in rabbits; and thus, there are no reports on production of transgenic rabbits by gene targeting.
