Thanks to a unique regulatory structure in the United Kingdom, researchers there have been able to experiment with combining human DNA in ways not allowed in other countries—most recently, perfecting the science of fertilizing an embryo with the DNA of three individuals in order to prevent infants from inheriting mitochondrial disease. The eggs from both the mother and the donor are fertilized in the lab with the dad’s sperm; the embryos develop until the DNA from the sperm and egg form the pro-nuclei; which are then removed from both embryos, and the parents’ DNA is put inside the embryo packed with healthy mitochondria. The resulting child is genetically related to their parents, but should be free from mitochondrial disease.
