A new genetic revolution, unfolding at unprecedented speed, is the focus of a three-day meeting in Washington that begun Tuesday and has brought hundreds of scientists to the nation’s capital to grapple with its vast potential, ranging from new treatments for genetic diseases to the creation of designer babies to what some see as an unpredictable “Brave New World” of permanently altered human heredity.
The technique, called gene editing, allows scientists to cut and paste the DNA that makes up human genes with speed and precision, inside living human cells. It can be used to repair damaged genes and to accelerate research into how genes function. It can also be used to transmit genetic traits to future generations, including through human sperm, eggs and embryos, which is now widely considered unethical.
Chinese researchers raised concerns worldwide when they reported in April that they had tinkered with genes in human embryos in an attempt to modify the gene responsible for beta-thalassaemia, a potentially deadly blood disorder. Such changes, some scientists warned, could permanently change the human genome with unknown consequences.
“We sense that we are close to being able to alter human heredity,” Nobel laureate David Baltimore of the California Institute of Technology said in his opening address to the three-day International Summit on Human Gene Editing: A Global Discussion, called he said, to consider “deep and disturbing questions” raised by the new genetic tools.
Unlike the last such meeting called to consider vexing implications of breakthrough genetic technology, the Asilomar Conference held in Pacific Grove, California, in 1975, this summit is unfolding in full public view on the Internet. It was convened by the National Academy of Scientists, the Chinese Academy of Sciences and the British Royal Society.
There are a few methods used for gene editing, but the version that has generated most of the excitement – and controversy – is called CRISPR-Cas9, a mechanism that bacteria use to repair their own DNA when it is damaged. It is much faster and far cheaper than other methods, biologists say. What makes the new technique so compelling, and so troubling to some, is how broadly it may be applied and how difficult it will be to regulate worldwide.
The possibility that the technique can be used to eliminate genetic disabilities and enhance human capabilities raises the specter of eugenics, a movement that emerged early in the 20th century, said Daniel Kevles, a New York University law professor, who expressed concern that the potential to enhance the genome could lead to unintended effects. “I like everyone else in the world am concerned with the implications of this new technique,” Kevles said.
The most controversial use of the new tools is to carry out what scientists dub “germline” editing, or altering the DNA in sperm, eggs and embryos to permanently eliminate disease-causing genes in future generations. “We still have a lot to learn and it might be a good idea, but before we make permanent changes to the human gene pool, we should exercise considerable caution,” says Eric Lander, director of the Broad Institute of MIT and Harvard.
“The truth is, if we really care about avoiding cases of genetic disease, germline editing is not the first, second, third, or fourth thing we should be thinking about,” he said. “Most people don’t know they’re at risk.” A better approach is ready access to genetic counseling and diagnosis, he said. Once couples know their risks, they can resort to in-vitro fertilization and pre-implantation genetic diagnosis of embryos, so that women can become pregnant with healthy embryos, not those carrying disease-causing genes.
Over the course of the meeting researchers will debate ways to make the best use of the new technology and minimize its drawbacks. “We’re probably going to need new review and oversight structures, on an international scale to make sure this technology is used appropriately,” said George Daley of Boston Children’s Hospital.
Creating designer babies is unlikely to rise to the top of the list, Daley said. “I’m skeptical of the brave new world of designer babies, because most of the complex traits we’d like to engineer– courage, intelligence and the like – are multifactorial, due to interplay of genes and environment.”