Generate cells using parthenogenesis, a form of asexual reproduction in which an embryo can develop without fertilization. Parthenogenesis occurs naturally in some plants and vertebrates, but not in mammals. However, scientists can trick mammalian eggs into undergoing parthenogenesis by activating the egg as if it had been fertilized. To date, such embryos have been generated in mice, primates, and even humans. Human versions of these embryos are called parthenotes; they survive only a few days and are therefore unable to develop into a human life.
Daley cautions that many tests still need to be done before such therapies can be developed for patients. For example, since parthenote cells carry two sets of maternal genes, they may have abnormal gene expression. “We will try to determine if cells made from parthenotes will function normally,” says Daley.