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 US FDA has approved Novartis to supply a gene therapy called Zolgensma, for treating spinal muscular atrophy (SMA).