Scientists in London have been granted permission to edit the genomes of human embryos for research, UK fertility regulators announced today. The approval on February 1 by the UK’s Human Fertilisation and Embryology Authority (HFEA) represents the world's first endorsement of such research by any national regulatory authority.

"It’s an important first. The HFEA has been a very thoughtful, deliberative body that has provided rational oversight of sensitive research areas, and this establishes a strong precedent for allowing this type of research to go forward," says George Daley, a stem-cell biologist at Children's Hospital Boston in Massachusetts.

The HFEA has approved an application by developmental biologist Kathy Niakan, at the Francis Crick Institute in London, to use the genome-editing technique CRISPR–Cas9 in healthy human embryos. Niakan’s team is interested in early development, and they plan to alter genes that are active in the first few days after conception. The researchers will stop the experiments after seven days, after which the embryos will be destroyed.

The genetic modifications could help researchers develop treatments for infertility, but the alterations would not themselves form the basis of a therapy.

Robin Lovell-Badge, a developmental biologist at the Francis Crick Institute, says that the HFEA’s decision will embolden other researchers who hope to edit the genomes of human embryos. He has heard from other UK scientists who are interested in pursuing embryo editing research, he says, and expects that more applications will follow. In other countries, he says, the decision “will give scientists confidence to either apply to their national regulatory bodies, if they have them, or just to go ahead anyway.” (For more on the future of gene editing, read our In-Depth Report, "Customized Human Genes: New Promises and Perils")

Kathy Niakan.

Francis Crick Institute

Development genes

Niakan’s team already had a licence with the HFEA to conduct research using healthy human embryos that are donated by patients at fertility clinics. But in September last year the team announced it had applied to conduct genome editing on these embryos—five months after researchers in China had reported experiments applying CRISPR–Cas9 genome editing to non-viable human embryos, which sparked a debate about how or whether to draw the line on gene-editing in human embryos.

At a press briefing last month, Niakan said her team could begin experiments within “months” if the HFEA approved the application. The first experiment will involve blocking the activity of a ‘master regulator’ gene called OCT4, which is active in the cells that go on to form the developing fetus (different cells in the embryo go on to form the placenta). Her team plans to end its test tube experiments within a week after fertilization, when the embryos contain around 64 to 256 cells, which is known as the blastocyst stage.

“I am delighted that the HFEA has approved Dr Niakan’s application,” Paul Nurse, the president of the Francis Crick Institute, said in a statement. “Dr Niakan’s proposed research is important for understanding how a healthy human embryo develops and will enhance our understanding of IVF success rates, by looking at the very earliest stage of human development—one to seven days.”

A local research ethics board (which is similar to an institutional review board in the United States) will also need to approve the research Niakan’s team have planned. In approving Niakan's application, the HFEA said no experiments could begin until this approval was granted.

International impact

Sarah Chan, a bioethicist at the University of Edinburgh, UK, says that the decision will reverberate well beyond the United Kingdom. “I think this will be a good example to countries who are considering their approach to regulating this technology. We can have a well-regulated system that is able to make that distinction between research and reproduction,” she says.

It remains illegal to alter the genomes of embryos used to conceive a child in the UK, but researchers say that the decision to allow embryo-editing research could inform the debate over deploying gene-editing in embryos for therapeutic uses in the clinic.

“This step in the UK will stimulate debate on legal regulation of germline gene editing in clinical settings,” says Tetsuya Ishii, a bioethicist at Hokkaido University in Sapporo, Japan, who notes that some countries do not explicitly prohibit reproductive applications.

“This type of research should prove valuable for understanding the many complex issues around germline editing," adds Daley. "Even though this work isn’t explicitly aiming toward the clinic, it may teach us the potential risks of considering clinical application.”

This article is reproduced with permission and was first published on February 1, 2016.