As the director of the Sculpting Evolution Group at the MIT Media Lab, Kevin Esvelt (K.E.) spends every day thinking about extinction. Esvelt is a biochemist, and he is developing a method to eradicate certain diseases before they eradicate us. Instead of tackling a disease after an infection, like most gene therapies would, Esvelt wants stop diseases before they strike. Using CRISPR/Cas9 gene editing and gene drive — a natural mechanism that preferentially pushes a gene from one generation to the next, Esvelt could, in theory, eliminate a disease by blocking the organisms that carries it (See Creating Complete Resistance with CRISPR/Cas9.) With CRISPR, Esvelt could, for example, block every mosquito in the world from carrying malaria. As beneficial as this sounds, it also makes many people nervous. Esvelt sat down with Elie Dolgin (E.D.) to discuss how to eliminate a disease and the sacrifices necessary to do so.
E.D. Can CRISPR actually eliminate diseases?
K.E.: For any animals that serve as vectors or reservoirs of disease, we should be able to build organisms that are programmed to be immune to every virus known to infect them. So, this would mean things like malaria, which is spread by mosquitos, or Ebola, which has a reservoir in bats, or Lyme disease, which is carried primarily through the white-footed mouse.
E.D. What makes CRISPR unique in this kind of disease fighting?
K.E.: CRISPR lets us harness a naturally occurring phenomenon called gene drive to spread genes of our choosing. This means that we could engineer an organism that would confer disease resistance to an entire species. Ideally, we’d want to start small and local, see how well it works, and only then scale up if it’s warranted.
E.D. What determines if it’s warranted?
K.E.: It has to be a very big problem indeed for people to be willing to alter an entire species, which is spread across many different nations, all of which would have to agreed — and they would all have to agree to do it without the benefit of a field trial to show that it’s safe and it works. Malaria is one of the only cases I can think of that fits the bill. A group called Target Malaria is working on this now, talking with lots of African countries at different levels, seeing if there can be a path to agreement.
E.D. And for other diseases like Lyme?
K.E.: Here’s the thing: Technically we could do it, but socially and diplomatically we can’t. So, what we need is a version of gene drive that can still amplify but is self-exhausting. Then every town could decide for itself whether it wanted this kind of local version of gene drive in their backyard. We’re still working on that system, but I’m not really worried about technical hurdles. The question is whether the technical solutions like this will be sufficient to solve the social and diplomatic problems.