The news that researchers have carried out the first known attempt to create genetically modified human embryos is another signpost in an astounding revolution unfolding before our eyes. This is not the first breakthrough nor will it be the last, but it should serve as a reminder - an unmistakable one - that this realm of scientific inquiry, manipulating the tiny building blocks of life, demands caution as well as enthusiasm and encouragement.
The latest effort, led by Shoukhrat Mitalipov of Oregon Health & Science University, with researchers from South Korea, China, the Salk Institute for Biological Studies in California and others, involved editing the DNA of single-cell embryos with CRISPR-Cas9, a tool for genome engineering that is much simpler, faster and cheaper than earlier methods, and which has sparked an explosion of interest in possible applications. According to a report published Wednesday in the journal Nature, the researchers were able to demonstrate that it is possible to safely and efficiently correct defective genes that cause inherited diseases.
The embryos they modified were not allowed to develop for more than a few days and were not implanted in a womb. In earlier research in China, the modified DNA was taken up by only some cells, not all, and suffered other setbacks, raising questions about its effectiveness. The latest research team reports it achieved “efficiency, accuracy and safety” with the approach.
If so, the research may be yet another step toward what is called germline engineering, or changing the genetic material in reproductive cells, so that any offspring would pass the changes on to future generations. The potential impact is huge; thousands of inherited diseases are caused by mutations in single genes, so editing the germline cells of individuals who carry these mutations could allow them to have children without the risk of passing on the conditions.
But the dangers and concerns are also significant. The technique could be used to enhance human traits beyond just eradicating disease, such as creating “designer babies,” or for other malevolent purposes. Genome editing was singled out for concern in a 2016 report to Congress from the U.S. intelligence community about potential wordwide threats: “Given the broad distribution, low cost, and accelerated pace of development of this dual-use technology, its deliberate or unintentional misuse might lead to far-reaching economic and national security implications.”
In a report this year, a panel of the National Academy of Sciences addressed the potential and the risks of germline engineering, concluding that basic research should proceed, closely watched. But the panel also said, “Do not proceed at this time with human genome editing for purposes other than treatment or prevention of disease and disability.” This seems to us to strike a reasonable balance, but one that will require vigilance - transparency, oversight and public awareness - to ensure the fruits of this remarkable revolution are not somehow abused or misused.