Noema: Gene editing may enable us to prevent a species from ever becoming extinct in the first place. But should we? It turns out playing God is neither difficult nor expensive. For about $2,000, I can go online and order a decent microscope, a precision injection rig, and a vial of enough CRISPR-Cas9 — an enzyme-based genome-editing tool — to genetically edit a few thousand fish embryos. In addition to this, I’ll need the hand-eye coordination of a middling video game player, a stack of petri dishes and an insulated box that can keep my edited embryos in the Goldilocks temperature zone of around 28.5 degrees Celsius. In fact, the most difficult part is getting a reliable supply of freshly fertilized zebrafish embryos for my experiments. Fortunately, at the Marine Biological Laboratory in Woods Hole, Massachusetts, where I spent 10 days in May learning how to do genetic editing, it’s not a problem. The lab can produce a new batch every hour, so I have plenty to work with. I line up dozens of single-cell embryos along the edge of a glass slide. Under the microscope, they look like a string of yellowed pearls. When I prod them with an ultra-fine glass syringe, they squish like tapioca balls in a boba tea. But if I get the angle right, I can inject them with a carefully calibrated dose of CRISPR-Cas9 designed to disable a gene associated with eye development. When they hatch into larvae a few days later, they will have no eyes. If I were to allow them to reach adulthood, which I won’t, they could theoretically breed with other similarly blinded adults to create a population of eyeless fish for an aquarium exhibit of unnatural wonders. The process is deceptively simple; the implications are anything but…”