Mankind has been manipulating genetics since early civilizations realized that certain traits of crops, animals and humans themselves were hereditary. The modern-day mapping of all human genes raised the prospects of learning precisely which genes control which traits and then directly altering their DNA codes. After years of hit-and-miss efforts, a gene-editing system called Crispr that's cheap, effective and easy to use promises to change our relationship with genetics — for better, worse or both. Its champions foresee using Crispr to control pests, increase food production and eliminate human diseases. They simultaneously worry that its use could unleash dangerous mutants, designer babies and new weapons of mass destruction. In the meantime, Crispr has given birth to a new biotechnology industry that is beginning to show promise in treating some intractable illnesses.
Because of Crispr's ability to cut and paste individual genes, companies have been working to use the technology to rectify DNA flaws that lead to inherited disease. Those efforts gained a strong push in late June when drugmakers Intellia Therapeutics Inc. and Regeneron Pharmaceuticals Inc. reported results from the first clinical trial using Crispr technology to treat disease inside the human body. In the early-stage trial of just six people, researchers used Crispr to edit out a flawed gene that results in production of an abnormal liver protein that accumulates throughout the body, sometimes causing severe and even lethal symptoms. While the study doesn’t prove the approach works, the patients who were treated saw significant reductions in levels of the harmful protein. In the past, gene editing had been used to alter human cells that were removed from the body and then replaced; the companies’ trial showed that that step isn’t always needed. Additional companies, such as Editas Medicine, are also working on similar projects. Other researchers have used Crispr inside the body, but not to treat disease. Chinese scientist He Jiankui announced in 2018 that he’d used the technology to alter the genes of a pair of twins while they were embryos with the aim of making them resistant to HIV. Using Crispr to make changes to embryos and germline cells — sperm, eggs and zygotes — is especially contentious because the modifications are passed to progeny. His announcement resulted in an ethical outcry and further restrictions on manipulating the DNA of healthy embryos.