Scientists from the Model Animal Research Center of Nanjing University in China published a paper in Cell last week detailing their use of the precision gene modifying technique CRISPR/Cas9 to alter targeted genes in monkey embryos, resulting in the first birth of primates following the new technique. Other scientists are currently working on the same feat, but Xingxu Huang and his colleagues are the first to report a successful live birth.
The news has garnered a lot of attention, much of it focused on hopes for more accurate animal models for research on complex human diseases. Though transgenic mice are often used for this purpose, primates offer a substantial advantage, especially for neurological disorders.
Not all observers are convinced that this technology will in fact prove useful for studying human disease. The genes that were altered in the monkeys – Ppar-y and Rag1 – are not directly linked to a particular disease, though they are associated with some disorders. Additionally, the researchers have not yet ascertained whether the mutations occurred in all of the animals’ cells, and of course their impact on the monkeys as they grow remains to be seen. As stem-cell researcher Rudolf Jaenisch told Nature, the results say little on their own. "The next step is to see if we can learn anything from it," Jaenisch said.
Despite this rather large caveat, some people are already looking toward applying this technique to humans. Coverage in MIT Technology Review did not shy away from discussing the prospect of creating GM humans.
"The fact that genome editing worked to create modified monkeys suggests it might also work to create genetically modified humans. Crispr is already used to modify human cells grown in labs, but it has not yet been tested on human embryos or adults. “We believe the success of this strategy in nonhuman primates gives lots of potential for its application in humans, but we think due to the safety issue, it will take a long way for expanding this strategy to human embryos,” says [study coauthor Wezhi] Ji."
Some coverage of the CRISPR monkeys identified experimental research on primates as the main ethical challenge raised by the research. The Guardian, for example, emphasized the concerns of animal rights advocates who warn that it could significantly increase the research use of non-human primates.
But scientists including George Church have already lined up the financing and launched a company called Editas that aims to use these precision gene editing technologies to treat a broad range of human diseases at the genetic level. Whether the company will also attempt to modify human embryos, leading to inheritable genetic modification, has not been clarified. In a February 6 webinar sponsored by Genetic Engineering & Biotechnology News, Church commented that human germline modification is “the ultimate in preventive medicine,” but that somatic modifications will likely be the focus for now, “until the safety and efficacy [of precision gene editing] is proven.”
We can recognize the beneficial potentials of CRISPR, and at the same time attend to its safety risks and to the door that it could open to eugenic enhancements. Acknowledging that prospect now is the first step toward ensuring that the social, ethical, and biopolitical implications of the work will guide, and not merely follow, the scientific research.