Most recently, experiments by Juan Carlos Izpisua Belmonte and his team at the Salk Institute created a human-monkey chimera embryo. It took four years, and the embryo successfully grew for a few ...

In work published in 2017, for instance, human cells contributed up to 1 percent of embryonic cells in a human-mouse chimera. In a study published today (April 15) in Cell, researchers describe their ...