S20-041 Igf1r Knockout to Increase Donor Cell Contribution in Interspecies Organ Generation Researchers in the Nakauchi lab at Stanford University have shown that the contribution of human donor cells to tissues and organs can be increased in an interspecies host embryo by knocking out insulin growth factor 1 receptor (Igf1r). Toshiya Nishimura Hiromitsu Nakauchi Motoo Watanabe