Will CRISPR gene-editing technology lead to designer babies?
来源：未知 作者：仪苁 时间：2017-06-20 02:01:21
By Michael le Page Genetically modified superhumans. Babies born with made-to-order characteristics. The idea has been explored in everything from academic journals to movies. CRISPR technology could make it a reality. The ability to alter human genes in a way that can be passed onto offspring, called germline engineering, has long been possible. But until recently the methods available to genetically modify animals were so inefficient and crude that no sane biologist would dream of using them on humans. Tinkering with the genes inside people has been limited to gene therapy, where the changes don’t get passed to the next generation (see “Is a new dawn of widespread gene therapy on the horizon?“). Now the precision and efficiency of CRISPR has reopened the debate about human germline engineering. But why do it? The most compelling reason would be to prevent the inheritance of genetic diseases, yet this is already being done without gene editing. One approach is prenatal testing, which involves screening for the disease-causing mutation during pregnancy, giving parents the option of abortion. Another is preimplantation genetic diagnosis (PGD), in which prospective parents who undergo IVF have their embryos screened. Only those that won’t develop the disease in question are then implanted. PGD can already be used to prevent thousands of serious genetic diseases. But PGD is impractical if a child is at risk of inheriting two or more disorders. For two disorders, three-quarters of embryos might be unsuitable – and with couples getting only a handful of embryos per IVF cycle,