The chimaeras of nature and their promise to grow human organs | Explained

Animals have long been used to fill the gap between organ donors and recipients. Recent advances in induced pluripotent stem cell technologies have enabled researchers to grow human organs in animals, raising ethical questions. Chimaeras, organisms composed of cells of more than one genotype, exist in nature and have been documented in humans. Bone marrow and organ transplants can also lead to chimerism. Scientists have successfully created a live chimaera in non-human primates, opening new doors for biomedical applications, but ethical issues must be addressed.