MIT Media Lab Evolutionary and Ecological Engineer Kevin Esvelt is on a mission to eradicate Lyme disease on Nantucket and Martha’s Vineyard, which have the second and third highest occurrences of tick-borne disease in the country. Kevin’s approach uses CRISPR to genetically modify white-footed mice, which carry Lyme in their blood and pass it on to biting ticks.
Profile: Kevin Esvelt
Published: September 26, 2018
Talithia Williams: Kevin Esvelt wants to stop a growing menace on Nantucket and Martha’s Vineyard, beautiful island communities off the coast of Massachusetts.
On the surface, you wouldn’t notice anything especially scary on nantucket. Tourists flock here and others live year-round to enjoy the beauty, fun, and comforts of island life. What they don’t come for, but often get anyway, is lyme disease.
Kevin Esvelt: Lyme is the single-most common infectious vector-born disease in the United States. It’s way more common than Zika. It’s way more common than West-Nile, anything like that. Here it is in Nantucket and Martha’s Vineyard at number two and number three when it comes to instances of tick-born disease in the United States.
Williams: Kevin Esvelt is on a mission to eradicate Lyme disease, and, for him, these Massachusetts islands are the perfect places to start. Humans get Lyme disease from ticks, but ticks are not born with Lyme bacteria. They get it by feeding on this innocent-looking critter, the white-footed mouse that carries Lyme bacteria in its blood. And another innocent-looking creature, the deer, is a crucial link in the chain of transmission to us.
Esvelt: But we like seeing deer, so, because there are so many more deer than there have ever been before, historically, there are many more ticks than there have ever been before.
Williams: For Kevin Esvelt, it's a risk people should not have to take, especially with their kids.
Esvelt: I’m from the west coast, and there, we have ticks, but they're so rare that I spent my childhood running around through the woods and never once got bitten by a tick, not once.
Noah, down the slide. Come on, I'm going to catch you. Whoa!
I have two kids, and it's just terrible that we have to be wary of them just running in the woods. So, the notion that you can wander out here through some of the worst areas and end up with lots of ticks on you is just, well, it's frankly horrifying.
Sam Telford: All right, so I have 40 traps out on this site.
Esvelt: Mice all seem to be wary today.
Williams: He believes he can get rid of Lyme disease by genetically altering the white-footed mice that carry it. And if that goes well, he hopes to edit their D.N.A., so they could resist ticks entirely.
Telford: Ahhh, looks like we've got one to take back.
Esvelt: Enlisting mice in the war against tick-borne disease would just be an amazing proposition.
The original idea that sparked this whole process was very simple. Animals like us, and also the mice, when we get sick with something, our immune systems evolve an antibody, often lots and lots of antibodies, that are really, really good at telling the immune system, "This is the enemy, kill it."
Williams: But these antibodies do not get passed on to our children, so we need vaccines to give us antibodies against certain diseases. But there is no human Lyme vaccine. And even if there was one for mice, he couldn't just line them up for shots. So, instead, Kevin wants to give them a genetic vaccine. Here's how that would work: first, Kevin, with the help of Sam Telford, infects mice in the lab with Lyme bacteria. These mice quickly develop robust, Lyme-resistant antibodies. Next, the team deciphers the genetic code that can create those antibodies. They make this antibody gene in the lab and inject it, along with CRISPR genes, into the developing sperm cells of Sam's lab mice. There, CRISPR would clear the way for the new gene to slide into the mouse's genome.
Now, if an engineered male mates with a wild female, roughly 50 percent of their babies, boys and girls, will inherit the Lyme-resistant gene and begin spreading it to future generations of mice. That is if Kevin's plan works.
But before he can even try, he'll need Nantucket residents to approve the release of genetically modified mice, something many people here worry might backfire. The power of genetic engineering to sculpt ourselves and the natural world does bring a burden of risk.
And although Kevin Esvelt is confident his engineered mice will only reduce Lyme disease and not bring harm to Nantucket's ecosystem, he also knows that absolute certainty and genetic engineering do not go together.
Esvelt: I worry every day that I might be missing something profound about the consequences of what we're developing.
Williams: At a town hall meeting, Kevin assures residents he will be taking a go slow approach…
Esvelt: Frankly, what we're talking about here is altering a shared environment.
Williams: …and that he could halt the experiment if problems appear. Most importantly, they would determine if the mice would ever get released here.
Esvelt: To be clear, this project will only move forwards if the community supports it at every step of the way.
Williams: He tells them he would first perform a field test on an isolated island to check that the new gene is working and the altered mice are causing no problems. Only then would he propose releasing them on Nantucket.
But for his new gene to spread throughout the mouse population, he would need to release a lot of engineered mice.
Esvelt: It might mean releasing say a hundred-thousand mice on Nantucket.
Williams: It would take that many to spread the Lyme-resistant gene effectively.
Richard Cooper: : What happens to the actual population, the mouse population, itself? I mean that's just going to keep growing and growing and growing.
Telford: Actually, no.
Williams: Although residents are concerned by the numbers, Sam Telford assures them the mice population will stay in check.
Telford: Something is out there that's regulating them. Disease is regulating them. There's a, a mite, a mange mite that is regulating them.
Williams: But even one G.M.O. mouse is still alarming for some.
Danica Conners: This is rapid, rapid man-made evolution.
Roberto Santamaria: Some people think that genetically modified organisms should never be done. They think that people like Kevin are playing God.
Conners: We don't know what effect it's going to have 15 years, 20 years, 25 years down the line.
Williams: But Kevin's cautious, open science approach seems to be winning the day.
Esvelt: If you were to run these kinds of experiments the way science is traditionally done, behind closed doors, you'd be denying people a voice in decisions intended to eventually affect them.
Timothy Lepore: Devin, why don't you come on down?
Williams: Islanders have given Kevin the go ahead to engineer the mice. But with a Nantucket release years away, there are no hard choices for them to make, yet. Still, residents here are so fed up with Lyme disease, if the field test does go well, Kevin's grand experiment could go all the way.
Kevin Esvelt is walking in the footsteps of those early pioneers who engineered bacteria to make insulin for diabetics. Today, we have the capacity to alter the genomes of every living thing. So, the potential rewards, and the risks, of genetic engineering have never been greater.
- NOVA Wonders Can We Make Life?
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