Viable rat-mouse chimeras: where do we go from here?
In a tour-de-force study, Kobayashi et al. (2010) describe the first viable rat-mouse chimeras and demonstrate that rat induced pluripotent stem (iPS) cells can rescue organ deficiency in mice. Rat iPS cells formed a fully functional pancreas when injected into mouse blastocysts lacking the Pdx1 gene required for pancreas formation.