RENEE MONTAGNE, HOST:
We are also tracking news this morning in science. Scientists have learned how to make genetic changes that spread through an entire species. The good news is that could become a powerful tool in the fight against diseases. The bad news? There may be unintended consequences. NPR's Rob Stein reports.
ROB STEIN, BYLINE: Ethan Bier runs a lab at the University of California San Diego. One day, his graduate student called him over and said, take a look at my experiment.
ETHAN BIER: It was one of the most astounding days in my personal scientific career, yeah. When he first showed me that, I could not believe it.
STEIN: His student, Valentino Gantz, had figured out how to genetically engineer brown fruit flies to produce nothing but blond offspring.
BIER: When the next generation came out and almost all the kids were blond, yeah, that was - we were just jumping up and down. Or at least I was. Valentino's a cooler character than me - but yeah, very exciting - very, very exciting.
STEIN: It may not sound like a big deal to turn fruit flies from brown to blond, but it was. It showed that scientists had a powerful new way to do genetic engineering, an easy way to permanently change an entire species incredibly fast.
BIER: I believe it's going to transform the world of genetics because it's going to allow researchers to bypass the rules of genetics in many different spheres of activity.
STEIN: Scientists have known for years how to genetically engineer all kinds of stuff, bacteria, plants, rats. Sometimes it passed down to their offspring. But this is a way to make it happen every time. It's done using a chunk of DNA called a gene drive.
BIER: The gene drive immediately makes the organisms that carry it have the characteristic. And then, secondly, it causes them to have all their children have the same characteristic.
STEIN: Scientists have known about gene drives for a long time, but they didn't have a good way to use them.
KEVIN ESVELT: All this changed two years ago, when several groups developed a protein that can be directed to precisely cut and therefore edit just about any DNA sequence in any organism.
STEIN: That's Kevin Esvelt, an evolutionary engineer who works on gene drives at Harvard. He says scientists realized something. They could use this very easy, precise new DNA editing trick to harness the power of gene drives. And one of the big things Esvelt says gene drives could do is eliminate some of the world's most terrible diseases, like malaria.
ESVELT: This is a disease that kills more than 1,000 children every day. So it's an urgent, urgent humanitarian issue. And now we have this technology that could potentially alter all the mosquitoes so that they can't carry malaria.
STEIN: And other diseases spread by mosquitoes and other insects, like West Nile, Dengue and Lyme disease, and that's just for starters. Scientists want to use gene drives to stop other bugs from eating crops so farmers could cut back on pesticides. There's even talk about genetically engineered bacteria to do lots of things, like eat oil spills.
ESVELT: It is potentially a way for us to interact with nature in a whole new way, using biology rather than bulldozers and toxic pesticides.
STEIN: This may all sound good, and it may be. But it makes a lot of people nervous.
BRENDAN PARENT: There are inherent problems with gene drives.
STEIN: Brendan Parent is a bioethicist at New York University. He says the major issue is uncertainty. No one knows what would happen if scientists start to release these genetically engineered creatures from their labs.
PARENT: We don't know what other impacts we're having. We don't know whether the elimination of malaria specifically won't somehow have genetic effects that cause a super-virulent pathogen to be released or to bring in much greater catastrophic consequences.
STEIN: You could cause mass extinctions, spread new diseases by upsetting the delicate balance of an ecosystem. Some even worry the technology could end up in the hands of terrorists. Stuart Newman is a biologist at New York Medical College.
STUART NEWMAN: If any group or country wanted to develop germ warfare agents, they could use techniques like this.
STEIN: Scientists working on gene drives say terrorists have much easier ways to attack people. But they do admit that gene drives are so potent that extra precautions are needed. Here's Harvard's Kevin Esvelt again.
NEWMAN: There are profound ethical issues here. That's why we need to handle this differently from the way that we'd traditionally handle scientific advances.
STEIN: So Esvelt, Bier and other scientists working with gene drives say they're being super careful to make sure their engineered insects and microbes don't escape by accident. They even plan to program them with genetic switches they could turn off if something bad does happen.
ESVELT: What that means is if someone makes a mistake, then we can undo that change.
STEIN: But critics are skeptical any of this is enough to make sure gene drives don't end up doing more harm than good. Rob Stein, NPR News.
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