Growth Competition in Interspecies Chimeras: A New Paradigm for Blastocyst Complementation

Blastocyst complementation represents a powerful technique for interspecies organogenesis but is limited by low chimerism due to developmental incompatibilities. In this issue of Cell Stem Cell,Nishimura et al. (2021) circumvent early developmental barriers by disabling Igf1r in host embryos, conferring donor cells with a growth advantage from mid-gestation onward. Blastocyst complementation represents a powerful technique for interspecies organogenesis but is limited by low chimerism due to developmental incompatibilities. In this issue of Cell Stem Cell, Nishimura et al. (2021) circumvent early developmental barriers by disabling Igf1r in host embryos, conferring donor cells with a growth advantage from mid-gestation onward.