You may be wondering why scientists would create a part-human part-monkey embryo — and you’re not alone.
An international team of scientists said they created hybrid embryos, or chimeras, to see if they could grow organs for people who need transplants. They published their findings in the medical journal, Cell.
The group assembled in China and injected 25 induced pluripotent stem cells, or iPS, from humans into embryos from macaque monkeys. According to the UCLA Broad Stem Cell Research Center, iPS are skin and blood cells that have been taken and reprogrammed to develop into any type of human cell needed for medical purposes. The cells can then be used to treat a variety of health issues including diabetes, leukemia or neurological disorders.
Scientists said they chose monkeys because other animals, like mice and pigs, have "a high evolutionary distance from humans."
The team soon noticed that the human cells were growing inside the monkey embryos, giving the scientists a chance to understand how human cells and animal cells communicate — a much-needed step to grow an organ, according to the study’s authors.
The scientists addressed ethical concerns in their report, acknowledging that they went through an extensive consulting process before conducting the study.
But they are defending their research.
"Our goal is not to generate any new organism, any monster," the experiment's co-author Juan Carlos Izpisua Belmonte told NPR. "And we are not doing anything like that. We are trying to understand how cells from different organisms communicate with one another."
The National Institutes of Health has been considering allowing human-animal embryos for research purposes, but has yet to make a final decision.
According to the American Transplant Foundation, nearly 114,000 people in the U.S. are on the waiting list for a life-saving organ transplant. On average, 20 people die every day from the lack of available organs needed for a transplant.
This story was reported from Los Angeles.