The following comes from an April 24 Science magazine article by Jocelyn Kaiser and Dennis Normile:
The announcement that a Chinese team had altered the genetics of a human embryo for the first time has ignited a firestorm of controversy around the world and renewed recent calls for a moratorium on any attempt to establish a pregnancy with such an engineered embryo.
But it has also underscored the fact that although scientists are united in their opposition to any clinical application of such embryo manipulation, they are split on the value of basic research that involves genetically modifying human embryos.
In China itself, where the precedent-setting research is big news and some in the public have expressed concern on the Internet about the embryo experiments, “most scientists are more positive,” says Guo-Qiang Chen, a microbiologist at Tsinghua University in Beijing. “My personal opinion is that as long as they can control the consequences they should continue this work.”
The paper at the heart of the debate, published online on 18 April in Protein & Cell, an obscure Chinese journal published by an affiliate of China’s Ministry of Education, drew widespread attention only after Nature News reported it online on 22 April. Junjiu Huang and colleagues at Sun Yat-sen University in Guangzhou described how they attempted to use the CRISPR/Cas-9 system, a new technology that makes it easy to modify genes in cells, to edit the hemoglobin-B gene (HBB) in 86 human embryos donated for research by couples at an in vitro fertilization (IVF) clinic. In theory, this could be a way to prevent beta thalassemia, a blood disorder that results when that gene is mutated, but the embryos experimented on were selected because they were not viable; they had an extra set of chromosomes as a result of being fertilized by two sperm.
The performance of the technique proved so poor that the researchers emphasized that any clinical use of CRISPR/Cas9 for embryo editing is “premature at this stage.” The project was reviewed by Huang’s university’s ethics board and complied with international and national ethical standards, according to the paper. The researchers used abnormal zygotes that would otherwise be discarded, “because ethical concerns preclude studies of gene editing in normal embryos,” they write.
Rumors that such a paper was in the works sparked several published opinion pieces a month ago. In a commentary in Science, molecular biologist David Baltimore, president emeritus of California Institute of Technology in Pasadena, and 17 co-authors called for scientists and others to “strongly discourage … attempts at germline genome modification for clinical application in humans.” (Many countries already ban or discourage germline gene modification.)
Several scientists led by Edward Lanphier, CEO of Sangamo BioSciences in Richmond, California, went further in a Nature commentary, calling for a voluntary moratorium on all experiments involving germline gene modification.
Regardless of where scientists stand on this new research, it has highlighted their shared desire to discuss whether, if ever, gene editing should be used in human embryos to prevent disease. University of California, Berkeley, molecular biologist Jennifer Doudna is now helping to organize an international meeting later this year to come up with guidelines. “I think the goal of that meeting is to come together and identify a broader consensus about the appropriate way to proceed with these experiments,” she says. Now that the first human embryo gene-editing paper has been published, she adds, “we feel some urgency.”