Japanese scientists have produced the first genetically modified monkeys that can pass on their new traits to offspring, a research breakthrough mired in ethical quandaries. The technique is meant to be used to infect monkeys with diseases like Parkinson’s and then test treatments on them, but could eventually be employed to modify humans, the Washington Post reports.
In the experiment, marmosets were injected with a jellyfish gene that caused them and their offspring to glow green in fluorescent light. Animal-rights groups say the breakthrough opens doors to legions of primates produced merely to suffer painful diseases and therapies. But proponents say scientists may use fewer animals in the long run, since monkeys are genetically closer to humans than lab mice.