A Spanish research team, led by Professor Juan Carlos Izpisua Belmonte, a researcher at the Catholic University of Murcia (UCAM), in collaboration with the Salk Institute in the US, conducted experiments which created cross-species organisms called chimeras, which have both human and animal DNAs. In this experiment, human stem cells were injected into the embryo or the fetus of genetically modified monkeys. Human stem cells later stimulated genes that played an essential role in organ formation. While the experiment should produce monkeys with human cells, the researchers later terminated the birth of the chimeras. The actual goal of the experiment was to find a way to treat rare human diseases by transplating organs from such chimeras into human patients.

          The experiments were conducted in China due to strict prohibition against such cross-species experiments in Spain, where such experiments are allowed only in certain vital circumstances, such as treatment of infectious and dangerous diseases. The research team viewed that the creation of chimeras could offer a possible solution for treatment of rare diseases, especially when patients need organ transplantation but no organ donors can be found and the patient’s body might reject a donated organ.