Scientists debate the ethics of an unnerving gene-editing technique Genetic engineering isn’t new, but CRISPR is, and it’s a stunningly fast, flexible, cheap way to manipulate the code of life. It’s so revolutionary — and unnerving — that hundreds of scientists, policymakers and the president’s science adviser gathered Tuesday in Washington for the start of a three-day
summit on the implications of this astonishing technology.


Developed only in the past four years, the CRISPR technique exploits a natural process used by ordinary bacteria to defend against invasive viruses. It enables rank-and-file scientists — just about anyone with a modern laboratory and the right skills — to alter specific genes within plants and animals and make those changes heritable. This kind of gene editing could potentially be used in gene therapies targeting a variety of devastating, heritable diseases.
But many researchers argue that it is too soon, and potentially too dangerous, to tinker with the human genome in a way that is passed down to future generations. One objection is simply pragmatic: Biological systems are extremely complex, and changing human genes could have unintended and undesirable consequences. And many bioethicists are not comfortable with the prospect that gene editing could be used for purely cosmetic enhancements, or in an attempt to give certain people physical and intellectual advantages.
“The overriding question is when, if ever, we will want to use gene editing to change human inheritance, » summit chair David Baltimore of Caltech said in his introductory remarks.

[The rumors were true: Scientists edited the genomes of human embryos for the first time]

The summit kicked off Tuesday morning at the headquarters of the National Academy of Sciences, which is one of the sponsors, along with the National Academy of Medicine, the Royal Society (United Kingdom), and the Chinese Academy of Sciences. The Chinese scientists have been aggressive in using CRISPR, and one team made news this year when it reported results from experiments on nonviable human embryos.
The first set of speakers put the summit in historical context. An Egyptian historian, Ismail Serageldin of the Library of Alexandria, offered a broad view of human engagement with the natural world: “We have been playing god ever since we domesticated plants and animals. »
Daniel Kevles, an emeritus historian at Yale, offered a tutorial on the eugenics movement in the early 20th century, noting that although it reached its genocidal zenith in Nazi Germany, it also had intellectual support in the United States on both ends of the political spectrum. He said that today, the driving force for human genetic modification will be consumer demand, with the biotech industry serving as « a new player in this game. »
Alta Charo, a professor of law and bioethics at the University of Wisconsin at Madison, reviewed the different approaches that countries have taken in trying to regulate gene therapy. She favored a precautionary approach that she said would not suppress innovation, arguing that responsible oversight would allow researchers to take more chances. « We have the chance to back up at the end, and change course, » she said.
The reason CRISPR is so controversial is that it works well on mammalian »germline » cells, such as sperm, eggs and embryonic cells, and the genetic editing can therefore result in heritable traits. Baltimore said he hopes the final session Thursday will produce recommendations for a path forward.

The CRISPR technique uses the Cas9 enzyme as a gene-snipper. If properly targeted, it can precisely edit genes. Getting to a high level of precision has been tricky to date, but researchers have made great strides in just the few years since the idea of using the enzyme for gene editing emerged from laboratories in Massachusetts and California. (Who, exactly, discovered the CRISPR technique and deserves the patents for it is a matter of intense legal wrangling.)

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