Nishimasu et al, 2014

Cas9, the enzyme used in the CRISPR/Cas9 genome-editing technique, employed on a stand of DNA.

While scientists around the world continue to debate the use of the CRISPR/Cas9 system, the tool capable of precisely editing DNA on the genomic level, British scientists working at the Francis Crick Institute in London announced today that they have applied for permission from the United Kingdom's fertility regulator (the UK Human Fertilization & Embryology Authority) to use this technique on viable human embryos. If granted, this would allow them to directly study humans' earliest stage of development and would mark the first approval by a national regulatory body to employ the CRISPR/Cas9 system on viable human embryos.

The use of the CRISPR/Cas9 system remains a controversial issue. This new announcement comes only a few months after an op-ed was published in Nature cautioning against its use, and after Chinese researchers reported they had indeed successfully employed the CRISPR/Cas9 system on non-viable human embryos to remove a part of the gene that causes a genetic blood condition called beta thalassemia.

Kathy Niakan, a group leader at Crick and lead author of the research, says her and her team plan to use CRISPR/Cas9 for basic research, with no intention of a clinical application. Further, the viable embryos would only be studied for two weeks and, by UK law, cannot be implanted for a successful pregnancy. However, the information gathered by this basic research could have broad clinical implications, particularly to improve the success rate for healthy embryonic development after in vitro fertilization as well as potential for use in stem cell research, according to the press release. Crick's announcement was first reported in an article in The Guardian.