Abstract

CRISPR keeps me up at night. I marvel at its potential to cure insidious genetic diseases and scourges like malaria. I shudder at the ways it might be misused to create biological weapons. What frightens me most, though, is what I can't predict: how will we use CRISPR? How will it change evolution? How will it redefine the very nature of our existence?CRISPR is an ingenious cut-and-paste system that homes in on a particular DNA gene sequence and then, using Cas9 enzymes, snips it out. That sequence is then replaced with a new one that rewrites or repairs the original. Two different cells—somatic, from the body, and germline, from gametes—can be manipulated...