Genetic engineering is often derided as "playing God." No technology approaches that metaphor more closely than the gene drive. A powerful and controversial technology, a gene drive is a form of genetic engineering that allows researchers in a lab to override the rules of natural selection.
The offspring of just about any sexually reproducing species typically inherits half of its genes from one parent and half from the other - a genetic Powerball drawing. A gene drive rigs the lottery, ensuring that a particular trait is passed down to all of one parent's offspring.
Now why would you want to do that? Scientists aren't trying to create superhumans. They're interested in gene drives as a solution to problems like disease and ecological devastation. Gene drives could be a revolutionary technological tool, capable of allowing scientists to engineer problematic invasive pests out of an environment, or change their genetic makeup permanently so that they don't carry diseases like malaria.
It works like this: Say an overpopulation of stoats, a predatory mammal related to weasels, is driving out endangered birds, as is the case in New Zealand. In the lab, scientists tweak a specific gene to, say, make stoats only produce male offspring, and then they engineer a gene drive to force that gene to be passed along to all the offspring, usurping nature's 50-50 inheritance mix. They would then release those lab-engineered stoats to mate in the wild, eventually causing the wild population to crash as the gene drive ensures that only male stoats are born. Effective, but impossible to control once the altered stoats have left the lab. (Watch the video above for more on stoats.)
The technology comes with some pretty major asterisks, though. First off, it's yet to be tested in the wild, so it might not work outside of lab conditions. And scientists have suggested that if it does, the genetically altered species could wind up becoming an invasive species itself -- even spreading globally, in a worst-case scenario, sparking domino effects that could be more harmful than the original problem.
Scientists are hard at work developing ways to allow the technology to be used both effectively and safely. If they figure it out, it could be a boon to conservation, health, and agriculture.