In March, a rumor surfaced in the scientific community that was intriguing, and perhaps a bit chilling: According to those in the know, researchers in China had successfully edited the genomes of human embryos, altering their DNA in a way never accomplished in our own species. MIT Technology Review reported on the murmurings that someone had altered the germ line — the genetic information that come together and form something new when eggs and sperm collide. Even unconfirmed, those rumors led to a lot of debate about the potential downsides of altering the germ line. Carl Zimmer has more on the controversy at his blog on National Geographic.
The work, led by Junjiu Huang of Sun Yat-sen University in Guangzhou, focused on modifying the gene responsible for β-thalassaemia, a blood disorder that can be fatal. They used CRISPR, a cutting-edge gene editing tool that’s already made serious waves in the genome editing of other species. By going after genes at the earliest stage of human development — in a single-celled embryo — theoretically one can make sure all the subsequent copies of the gene are the superior version. But we have a long way to go before that’s actually the case.