[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.84,0:00:03.31,Default,,0000,0000,0000,,So this is a talk about gene drives,
Dialogue: 0,0:00:03.33,0:00:05.88,Default,,0000,0000,0000,,but I'm going to start\Nby telling you a brief story.
Dialogue: 0,0:00:06.62,0:00:09.84,Default,,0000,0000,0000,,20 years ago, a biologist\Nnamed Anthony James
Dialogue: 0,0:00:09.87,0:00:12.19,Default,,0000,0000,0000,,got obsessed with the idea\Nof making mosquitos
Dialogue: 0,0:00:12.21,0:00:14.79,Default,,0000,0000,0000,,that didn't transmit malaria.
Dialogue: 0,0:00:15.68,0:00:19.74,Default,,0000,0000,0000,,It was a great idea,\Nand pretty much a complete failure.
Dialogue: 0,0:00:20.60,0:00:23.26,Default,,0000,0000,0000,,For one thing, it turned out\Nto be really hard
Dialogue: 0,0:00:23.28,0:00:25.29,Default,,0000,0000,0000,,to make a malaria-resistant mosquito.
Dialogue: 0,0:00:26.29,0:00:29.91,Default,,0000,0000,0000,,James managed it, finally,\Njust a few years ago,
Dialogue: 0,0:00:29.94,0:00:32.01,Default,,0000,0000,0000,,by adding some genes\Nthat make it impossible
Dialogue: 0,0:00:32.03,0:00:34.75,Default,,0000,0000,0000,,for the malaria parasite\Nto survive inside the mosquito.
Dialogue: 0,0:00:35.55,0:00:37.37,Default,,0000,0000,0000,,But that just created another problem.
Dialogue: 0,0:00:38.04,0:00:40.88,Default,,0000,0000,0000,,Now that you've got\Na malaria-resistant mosquito,
Dialogue: 0,0:00:40.91,0:00:44.50,Default,,0000,0000,0000,,how do you get it to replace\Nall the malaria-carrying mosquitos?
Dialogue: 0,0:00:46.11,0:00:47.58,Default,,0000,0000,0000,,There are a couple options,
Dialogue: 0,0:00:47.60,0:00:49.63,Default,,0000,0000,0000,,but plan A was basically to breed up
Dialogue: 0,0:00:49.65,0:00:52.74,Default,,0000,0000,0000,,a bunch of the new\Ngenetically-engineered mosquitos
Dialogue: 0,0:00:52.76,0:00:54.09,Default,,0000,0000,0000,,release them into the wild
Dialogue: 0,0:00:54.11,0:00:56.08,Default,,0000,0000,0000,,and hope that they pass on their genes.
Dialogue: 0,0:00:56.67,0:00:58.79,Default,,0000,0000,0000,,The problem was that you'd have to release
Dialogue: 0,0:00:58.81,0:01:03.11,Default,,0000,0000,0000,,literally 10 times the number\Nof native mosquitos to work.
Dialogue: 0,0:01:03.14,0:01:05.22,Default,,0000,0000,0000,,So in a village with 10,000 mosquitos,
Dialogue: 0,0:01:05.25,0:01:07.32,Default,,0000,0000,0000,,you release an extra 100,000.
Dialogue: 0,0:01:08.23,0:01:09.38,Default,,0000,0000,0000,,As you might guess,
Dialogue: 0,0:01:09.40,0:01:12.16,Default,,0000,0000,0000,,this was not a very popular strategy\Nwith the villagers.
Dialogue: 0,0:01:12.18,0:01:13.33,Default,,0000,0000,0000,,(Laughter)
Dialogue: 0,0:01:14.96,0:01:18.67,Default,,0000,0000,0000,,Then, last January,\NAnthony James got an email
Dialogue: 0,0:01:18.69,0:01:20.64,Default,,0000,0000,0000,,from a biologist named Ethan Bier.
Dialogue: 0,0:01:21.40,0:01:24.26,Default,,0000,0000,0000,,Bier said that he\Nand his grad student Valentino Gantz
Dialogue: 0,0:01:24.28,0:01:27.23,Default,,0000,0000,0000,,had stumbled on a tool\Nthat could not only guarantee
Dialogue: 0,0:01:27.25,0:01:29.92,Default,,0000,0000,0000,,that a particular genetic trait\Nwould be inherited,
Dialogue: 0,0:01:29.95,0:01:32.03,Default,,0000,0000,0000,,but that it would spread\Nincredibly quickly.
Dialogue: 0,0:01:32.73,0:01:35.40,Default,,0000,0000,0000,,If they were right,\Nit would basically solve the problem
Dialogue: 0,0:01:35.42,0:01:37.80,Default,,0000,0000,0000,,that he and James had been\Nworking on for 20 years.
Dialogue: 0,0:01:38.45,0:01:43.11,Default,,0000,0000,0000,,As a test, they engineered two mosquitos\Nto carry the anti-malaria gene
Dialogue: 0,0:01:43.13,0:01:45.29,Default,,0000,0000,0000,,and also this new tool, a gene drive,
Dialogue: 0,0:01:45.32,0:01:46.81,Default,,0000,0000,0000,,which I'll explain in a minute.
Dialogue: 0,0:01:47.51,0:01:49.84,Default,,0000,0000,0000,,Finally, they set it up\Nso that any mosquitos
Dialogue: 0,0:01:49.86,0:01:51.80,Default,,0000,0000,0000,,that had inherited the anti-malaria gene
Dialogue: 0,0:01:51.82,0:01:55.82,Default,,0000,0000,0000,,wouldn't have the usual white eyes,\Nbut would instead have red eyes.
Dialogue: 0,0:01:56.68,0:01:58.73,Default,,0000,0000,0000,,That was pretty much just for convenience
Dialogue: 0,0:01:58.76,0:02:01.29,Default,,0000,0000,0000,,so they could tell just at a glance\Nwhich was which.
Dialogue: 0,0:02:02.19,0:02:04.95,Default,,0000,0000,0000,,So they took their two\Nanti-malarial, red-eyed mosquitos
Dialogue: 0,0:02:04.97,0:02:07.63,Default,,0000,0000,0000,,and put them in a box\Nwith 30 ordinary white-eyed ones,
Dialogue: 0,0:02:07.66,0:02:08.83,Default,,0000,0000,0000,,and let them breed.
Dialogue: 0,0:02:09.38,0:02:13.24,Default,,0000,0000,0000,,In two generations, those had produced\N3,800 grandchildren.
Dialogue: 0,0:02:14.22,0:02:16.01,Default,,0000,0000,0000,,That is not the surprising part.
Dialogue: 0,0:02:16.72,0:02:18.64,Default,,0000,0000,0000,,This is the surprising part:
Dialogue: 0,0:02:18.66,0:02:21.57,Default,,0000,0000,0000,,given that you started\Nwith just two red-eyed mosquitos
Dialogue: 0,0:02:21.59,0:02:22.93,Default,,0000,0000,0000,,and 30 white-eyed ones,
Dialogue: 0,0:02:22.95,0:02:25.71,Default,,0000,0000,0000,,you expect mostly white-eyed descendants.
Dialogue: 0,0:02:26.51,0:02:29.54,Default,,0000,0000,0000,,Instead, when James opened the box,
Dialogue: 0,0:02:29.56,0:02:32.90,Default,,0000,0000,0000,,all 3,800 mosquitos had red eyes.
Dialogue: 0,0:02:33.32,0:02:35.36,Default,,0000,0000,0000,,When I asked Ethan Bier about this moment,
Dialogue: 0,0:02:35.38,0:02:38.89,Default,,0000,0000,0000,,he became so excited that he was literally\Nshouting into the phone.
Dialogue: 0,0:02:39.89,0:02:42.05,Default,,0000,0000,0000,,That's because getting\Nonly red-eyed mosquitos
Dialogue: 0,0:02:42.07,0:02:45.02,Default,,0000,0000,0000,,violates a rule that is the absolute\Ncornerstone of biology,
Dialogue: 0,0:02:45.04,0:02:46.29,Default,,0000,0000,0000,,Mendelian genetics.
Dialogue: 0,0:02:46.91,0:02:48.08,Default,,0000,0000,0000,,I'll keep this quick,
Dialogue: 0,0:02:48.10,0:02:50.87,Default,,0000,0000,0000,,but Mendelian genetics\Nsays when a male and a female mate,
Dialogue: 0,0:02:50.89,0:02:53.54,Default,,0000,0000,0000,,their baby inherits half\Nof its DNA from each parent.
Dialogue: 0,0:02:53.56,0:02:57.15,Default,,0000,0000,0000,,So if our original mosquito was aa\Nand our new mosquito is aB,
Dialogue: 0,0:02:57.18,0:02:58.98,Default,,0000,0000,0000,,where B is the anti-malarial gene,
Dialogue: 0,0:02:59.00,0:03:01.39,Default,,0000,0000,0000,,the babies should come out\Nin four permutations:
Dialogue: 0,0:03:01.42,0:03:03.99,Default,,0000,0000,0000,,aa, aB, aa, Ba.
Dialogue: 0,0:03:04.88,0:03:07.17,Default,,0000,0000,0000,,Instead, with the new gene drive,
Dialogue: 0,0:03:07.20,0:03:08.71,Default,,0000,0000,0000,,they all came out aB.
Dialogue: 0,0:03:09.90,0:03:12.45,Default,,0000,0000,0000,,Biologically, that shouldn't\Neven be possible.
Dialogue: 0,0:03:12.48,0:03:13.78,Default,,0000,0000,0000,,So what happened?
Dialogue: 0,0:03:14.71,0:03:16.15,Default,,0000,0000,0000,,The first thing that happened
Dialogue: 0,0:03:16.18,0:03:19.45,Default,,0000,0000,0000,,was the arrival of a gene-editing tool\Nknown as CRISPR in 2012.
Dialogue: 0,0:03:20.70,0:03:22.81,Default,,0000,0000,0000,,Many of you have probably\Nheard about CRISPR,
Dialogue: 0,0:03:22.84,0:03:26.14,Default,,0000,0000,0000,,so I'll just say briefly that CRISPR\Nis a tool that allows researchers
Dialogue: 0,0:03:26.16,0:03:28.74,Default,,0000,0000,0000,,to edit genes very precisely,\Neasily and quickly.
Dialogue: 0,0:03:29.53,0:03:33.26,Default,,0000,0000,0000,,It does this by harnessing a mechanism\Nthat already existed in bacteria.
Dialogue: 0,0:03:33.29,0:03:35.91,Default,,0000,0000,0000,,Basically, there's a protein\Nthat acts like a scissors
Dialogue: 0,0:03:35.94,0:03:37.17,Default,,0000,0000,0000,,and cuts the DNA,
Dialogue: 0,0:03:37.19,0:03:39.68,Default,,0000,0000,0000,,and there's an RNA molecule\Nthat directs the scissors
Dialogue: 0,0:03:39.70,0:03:41.42,Default,,0000,0000,0000,,to any point on the genome you want.
Dialogue: 0,0:03:41.44,0:03:44.13,Default,,0000,0000,0000,,The result is basically\Na word processor for genes.
Dialogue: 0,0:03:44.16,0:03:46.78,Default,,0000,0000,0000,,You can take an entire gene\Nout, put one in,
Dialogue: 0,0:03:46.81,0:03:49.25,Default,,0000,0000,0000,,or even edit just a single\Nletter within a gene.
Dialogue: 0,0:03:49.65,0:03:51.60,Default,,0000,0000,0000,,And you can do it in nearly any species.
Dialogue: 0,0:03:53.33,0:03:57.04,Default,,0000,0000,0000,,OK, remember how I said that gene drives\Noriginally had two problems?
Dialogue: 0,0:03:57.84,0:04:00.96,Default,,0000,0000,0000,,The first was that it was hard\Nto engineer a mosquito
Dialogue: 0,0:04:00.98,0:04:02.37,Default,,0000,0000,0000,,to be malaria-resistant.
Dialogue: 0,0:04:02.39,0:04:04.52,Default,,0000,0000,0000,,That's basically gone now,\Nthanks to CRISPR.
Dialogue: 0,0:04:05.12,0:04:06.88,Default,,0000,0000,0000,,But the other problem was logistical.
Dialogue: 0,0:04:07.31,0:04:09.11,Default,,0000,0000,0000,,How do you get your trait to spread?
Dialogue: 0,0:04:10.20,0:04:11.67,Default,,0000,0000,0000,,This is where it gets clever.
Dialogue: 0,0:04:12.94,0:04:16.54,Default,,0000,0000,0000,,A couple years ago, a biologist\Nat Harvard named Kevin Esvelt
Dialogue: 0,0:04:16.57,0:04:17.92,Default,,0000,0000,0000,,wondered what would happen
Dialogue: 0,0:04:17.94,0:04:21.57,Default,,0000,0000,0000,,if you made it so that\NCRISPR inserted not only your new gene
Dialogue: 0,0:04:21.59,0:04:24.44,Default,,0000,0000,0000,,but also the machinery\Nthat does the cutting and pasting.
Dialogue: 0,0:04:25.23,0:04:29.07,Default,,0000,0000,0000,,In other words, what if CRISPR\Nalso copied and pasted itself.
Dialogue: 0,0:04:30.14,0:04:33.28,Default,,0000,0000,0000,,You'd end up with a perpetual\Nmotion machine for gene editing.
Dialogue: 0,0:04:34.46,0:04:36.19,Default,,0000,0000,0000,,And that's exactly what happened.
Dialogue: 0,0:04:37.04,0:04:39.92,Default,,0000,0000,0000,,This CRISPR gene drive that Esvelt created
Dialogue: 0,0:04:39.94,0:04:43.58,Default,,0000,0000,0000,,not only guarantees\Nthat a trait will get passed on,
Dialogue: 0,0:04:43.61,0:04:46.04,Default,,0000,0000,0000,,but if it's used in the germline cells,
Dialogue: 0,0:04:46.07,0:04:48.64,Default,,0000,0000,0000,,it will automatically copy and paste\Nyour new gene
Dialogue: 0,0:04:48.67,0:04:51.31,Default,,0000,0000,0000,,into both chromosomes\Nof every single individual.
Dialogue: 0,0:04:51.74,0:04:54.14,Default,,0000,0000,0000,,It's like a global search and replace,
Dialogue: 0,0:04:54.16,0:04:57.38,Default,,0000,0000,0000,,or in science terms, it makes\Na heterozygous trait homozygous.
Dialogue: 0,0:04:59.04,0:05:01.66,Default,,0000,0000,0000,,So, what does this mean?
Dialogue: 0,0:05:01.68,0:05:04.40,Default,,0000,0000,0000,,For one thing, it means we have\Na very powerful,
Dialogue: 0,0:05:04.43,0:05:07.08,Default,,0000,0000,0000,,but also somewhat alarming new tool.
Dialogue: 0,0:05:08.58,0:05:11.46,Default,,0000,0000,0000,,Up until now, the fact that gene drives\Ndidn't work very well
Dialogue: 0,0:05:11.49,0:05:12.97,Default,,0000,0000,0000,,was actually kind of a relief.
Dialogue: 0,0:05:13.42,0:05:16.11,Default,,0000,0000,0000,,Normally when we mess around\Nwith an organism's genes,
Dialogue: 0,0:05:16.13,0:05:18.48,Default,,0000,0000,0000,,we make that thing\Nless evolutionarily fit.
Dialogue: 0,0:05:18.50,0:05:21.34,Default,,0000,0000,0000,,So biologists can make\Nall the mutant fruit flies they want
Dialogue: 0,0:05:21.36,0:05:22.61,Default,,0000,0000,0000,,without worrying about it.
Dialogue: 0,0:05:22.64,0:05:25.64,Default,,0000,0000,0000,,If some escape, natural selection\Njust takes care of them.
Dialogue: 0,0:05:26.75,0:05:29.97,Default,,0000,0000,0000,,What's remarkable and powerful\Nand frightening about gene drives
Dialogue: 0,0:05:29.100,0:05:31.76,Default,,0000,0000,0000,,is that that will no longer be true.
Dialogue: 0,0:05:33.09,0:05:36.66,Default,,0000,0000,0000,,Assuming that your trait does not have\Na big evolutionary handicap,
Dialogue: 0,0:05:36.68,0:05:38.76,Default,,0000,0000,0000,,like a mosquito that can't fly,
Dialogue: 0,0:05:38.78,0:05:42.24,Default,,0000,0000,0000,,the CRISPR-based gene drive\Nwill spread the change relentlessly
Dialogue: 0,0:05:42.26,0:05:45.27,Default,,0000,0000,0000,,until it is in every single individual\Nin the population.
Dialogue: 0,0:05:47.10,0:05:49.99,Default,,0000,0000,0000,,Now, it isn't easy to make\Na gene drive that works that well,
Dialogue: 0,0:05:50.01,0:05:52.19,Default,,0000,0000,0000,,but James and Esvelt think that we can.
Dialogue: 0,0:05:53.34,0:05:57.16,Default,,0000,0000,0000,,The good news is that this opens\Nthe door to some remarkable things.
Dialogue: 0,0:05:57.19,0:05:59.09,Default,,0000,0000,0000,,If you put an anti-malarial gene drive
Dialogue: 0,0:05:59.12,0:06:01.32,Default,,0000,0000,0000,,in just 1 percent of Anopheles mosquitoes,
Dialogue: 0,0:06:01.34,0:06:03.09,Default,,0000,0000,0000,,the species that transmits malaria,
Dialogue: 0,0:06:03.49,0:06:07.61,Default,,0000,0000,0000,,researchers estimate that it would spread\Nto the entire population in a year.
Dialogue: 0,0:06:08.18,0:06:11.05,Default,,0000,0000,0000,,So in a year, you could virtually\Neliminate malaria.
Dialogue: 0,0:06:11.46,0:06:15.33,Default,,0000,0000,0000,,In practice, we're still a few years out\Nfrom being able to do that,
Dialogue: 0,0:06:15.35,0:06:18.07,Default,,0000,0000,0000,,but still, a 1,000 children\Na day die of malaria.
Dialogue: 0,0:06:18.09,0:06:20.28,Default,,0000,0000,0000,,In a year, that number\Ncould be almost zero.
Dialogue: 0,0:06:20.97,0:06:23.86,Default,,0000,0000,0000,,The same goes for dengue fever,\Nchikungunya, yellow fever.
Dialogue: 0,0:06:25.21,0:06:26.62,Default,,0000,0000,0000,,And it gets better.
Dialogue: 0,0:06:27.22,0:06:29.69,Default,,0000,0000,0000,,Say you want to get rid\Nof an invasive species,
Dialogue: 0,0:06:29.72,0:06:31.84,Default,,0000,0000,0000,,like get Asian carp\Nout of the Great Lakes.
Dialogue: 0,0:06:32.43,0:06:34.46,Default,,0000,0000,0000,,All you have to do is release a gene drive
Dialogue: 0,0:06:34.48,0:06:36.80,Default,,0000,0000,0000,,that makes the fish produce\Nonly male offspring.
Dialogue: 0,0:06:37.39,0:06:41.58,Default,,0000,0000,0000,,In a few generations,\Nthere'll be no females left, no more carp.
Dialogue: 0,0:06:41.61,0:06:44.69,Default,,0000,0000,0000,,In theory, this means we could restore\Nhundreds of native species
Dialogue: 0,0:06:44.71,0:06:46.38,Default,,0000,0000,0000,,that have been pushed to the brink.
Dialogue: 0,0:06:47.41,0:06:50.70,Default,,0000,0000,0000,,OK, that's the good news,
Dialogue: 0,0:06:50.72,0:06:52.01,Default,,0000,0000,0000,,this is the bad news.
Dialogue: 0,0:06:53.07,0:06:55.10,Default,,0000,0000,0000,,Gene drives are so effective
Dialogue: 0,0:06:55.12,0:06:58.95,Default,,0000,0000,0000,,that even an accidental release\Ncould change an entire species,
Dialogue: 0,0:06:58.97,0:07:00.16,Default,,0000,0000,0000,,and often very quickly.
Dialogue: 0,0:07:01.18,0:07:03.30,Default,,0000,0000,0000,,Anthony James took good precautions.
Dialogue: 0,0:07:03.33,0:07:05.49,Default,,0000,0000,0000,,He bred his mosquitos\Nin a bio-containment lab
Dialogue: 0,0:07:05.52,0:07:08.11,Default,,0000,0000,0000,,and he also used a species\Nthat's not native to the US
Dialogue: 0,0:07:08.13,0:07:09.68,Default,,0000,0000,0000,,so that even if some did escape,
Dialogue: 0,0:07:09.71,0:07:12.72,Default,,0000,0000,0000,,they'd just die off, there'd be nothing\Nfor them to mate with.
Dialogue: 0,0:07:12.75,0:07:16.77,Default,,0000,0000,0000,,But it's also true that if a dozen\NAsian carp with the all-male gene drive
Dialogue: 0,0:07:16.80,0:07:20.72,Default,,0000,0000,0000,,accidentally got carried\Nfrom the Great Lakes back to Asia,
Dialogue: 0,0:07:20.75,0:07:24.18,Default,,0000,0000,0000,,they could potentially wipe out\Nthe native Asian carp population.
Dialogue: 0,0:07:25.93,0:07:28.84,Default,,0000,0000,0000,,And that's not so unlikely,\Ngiven how connected our world is.
Dialogue: 0,0:07:28.87,0:07:31.44,Default,,0000,0000,0000,,In fact, it's why we have\Nan invasive species problem.
Dialogue: 0,0:07:31.91,0:07:33.08,Default,,0000,0000,0000,,And that's fish.
Dialogue: 0,0:07:33.43,0:07:36.02,Default,,0000,0000,0000,,Things like mosquitos and fruit flies,
Dialogue: 0,0:07:36.04,0:07:38.00,Default,,0000,0000,0000,,there's literally no way to contain them.
Dialogue: 0,0:07:38.02,0:07:40.14,Default,,0000,0000,0000,,They cross borders\Nand oceans all the time.
Dialogue: 0,0:07:41.75,0:07:43.94,Default,,0000,0000,0000,,OK, the other piece of bad news
Dialogue: 0,0:07:43.96,0:07:46.28,Default,,0000,0000,0000,,is that a gene drive\Nmight not stay confined
Dialogue: 0,0:07:46.30,0:07:48.12,Default,,0000,0000,0000,,to what we call the target species.
Dialogue: 0,0:07:48.56,0:07:50.06,Default,,0000,0000,0000,,That's because of gene flow,
Dialogue: 0,0:07:50.08,0:07:52.68,Default,,0000,0000,0000,,which is a fancy way of saying\Nthat neighboring species
Dialogue: 0,0:07:52.70,0:07:53.95,Default,,0000,0000,0000,,sometimes interbreed.
Dialogue: 0,0:07:53.97,0:07:57.12,Default,,0000,0000,0000,,If that happens, it's possible\Na gene drive could cross over,
Dialogue: 0,0:07:57.15,0:07:59.67,Default,,0000,0000,0000,,like Asian carp could infect\Nsome other kind of carp.
Dialogue: 0,0:07:59.70,0:08:03.41,Default,,0000,0000,0000,,That's not so bad if your drive\Njust promotes a trait, like eye color.
Dialogue: 0,0:08:03.44,0:08:05.68,Default,,0000,0000,0000,,In fact, there's a decent\Nchance that we'll see
Dialogue: 0,0:08:05.71,0:08:08.28,Default,,0000,0000,0000,,a wave of very weird fruit flies\Nin the near future.
Dialogue: 0,0:08:09.39,0:08:10.65,Default,,0000,0000,0000,,But it could be a disaster
Dialogue: 0,0:08:10.68,0:08:13.58,Default,,0000,0000,0000,,if your drive is deigned\Nto eliminate the species entirely.
Dialogue: 0,0:08:14.35,0:08:17.88,Default,,0000,0000,0000,,The last worrisome thing\Nis that the technology to do this,
Dialogue: 0,0:08:17.90,0:08:21.59,Default,,0000,0000,0000,,to genetically engineer an organism\Nand include a gene drive,
Dialogue: 0,0:08:21.62,0:08:24.95,Default,,0000,0000,0000,,is something that basically any lab\Nin the world can do.
Dialogue: 0,0:08:24.98,0:08:26.32,Default,,0000,0000,0000,,An undergraduate can do it.
Dialogue: 0,0:08:27.21,0:08:30.49,Default,,0000,0000,0000,,A talented high schooler\Nwith some equipment can do it.
Dialogue: 0,0:08:32.53,0:08:34.84,Default,,0000,0000,0000,,Now, I'm guessing\Nthat this sounds terrifying.
Dialogue: 0,0:08:35.35,0:08:37.56,Default,,0000,0000,0000,,(Laughter)
Dialogue: 0,0:08:37.58,0:08:40.47,Default,,0000,0000,0000,,Interestingly though,\Nnearly every scientist I talk to
Dialogue: 0,0:08:40.50,0:08:44.38,Default,,0000,0000,0000,,seemed to think that gene drives were not\Nactually that frightening or dangerous.
Dialogue: 0,0:08:44.40,0:08:47.03,Default,,0000,0000,0000,,Partly because they believe\Nthat scientists will be
Dialogue: 0,0:08:47.05,0:08:49.26,Default,,0000,0000,0000,,very cautious and responsible\Nabout using them.
Dialogue: 0,0:08:49.28,0:08:50.29,Default,,0000,0000,0000,,(Laughter)
Dialogue: 0,0:08:50.32,0:08:51.55,Default,,0000,0000,0000,,So far, that's been true.
Dialogue: 0,0:08:52.30,0:08:54.100,Default,,0000,0000,0000,,But gene drives also have\Nsome actual limitations.
Dialogue: 0,0:08:55.02,0:08:58.33,Default,,0000,0000,0000,,So for one thing, they work\Nonly in sexually reproducing species.
Dialogue: 0,0:08:58.70,0:09:02.13,Default,,0000,0000,0000,,So thank goodness, they can't be used\Nto engineer viruses or bacteria.
Dialogue: 0,0:09:02.16,0:09:05.35,Default,,0000,0000,0000,,Also, the trait spreads\Nonly with each successive generation.
Dialogue: 0,0:09:05.37,0:09:07.36,Default,,0000,0000,0000,,So changing or eliminating a population
Dialogue: 0,0:09:07.39,0:09:10.71,Default,,0000,0000,0000,,is practical only if that species\Nhas a fast reproductive cycle,
Dialogue: 0,0:09:10.74,0:09:13.54,Default,,0000,0000,0000,,like insects or maybe\Nsmall vertebrates like mice or fish.
Dialogue: 0,0:09:14.44,0:09:16.70,Default,,0000,0000,0000,,In elephants or people,\Nit would take centuries
Dialogue: 0,0:09:16.72,0:09:19.10,Default,,0000,0000,0000,,for a trait to spread\Nwidely enough to matter.
Dialogue: 0,0:09:20.08,0:09:25.22,Default,,0000,0000,0000,,Also, even with CRISPR, it's not that easy\Nto engineer a truly devastating trait.
Dialogue: 0,0:09:26.08,0:09:27.81,Default,,0000,0000,0000,,Say you wanted to make a fruit fly
Dialogue: 0,0:09:27.83,0:09:30.39,Default,,0000,0000,0000,,that feeds on ordinary fruit\Ninstead of rotting fruit,
Dialogue: 0,0:09:30.41,0:09:33.04,Default,,0000,0000,0000,,with the aim of sabotaging\NAmerican agriculture.
Dialogue: 0,0:09:33.07,0:09:34.60,Default,,0000,0000,0000,,First, you'd have to figure out
Dialogue: 0,0:09:34.62,0:09:37.39,Default,,0000,0000,0000,,which genes control\Nwhat the fly wants to eat,
Dialogue: 0,0:09:37.42,0:09:39.96,Default,,0000,0000,0000,,which is already a very long\Nand complicated project.
Dialogue: 0,0:09:40.49,0:09:43.79,Default,,0000,0000,0000,,Then you'd have to alter those genes\Nto change the fly's behavior
Dialogue: 0,0:09:43.82,0:09:45.36,Default,,0000,0000,0000,,to whatever you'd want it to be,
Dialogue: 0,0:09:45.38,0:09:48.18,Default,,0000,0000,0000,,which is an even longer\Nand more complicated project.
Dialogue: 0,0:09:48.20,0:09:49.52,Default,,0000,0000,0000,,And it might not even work,
Dialogue: 0,0:09:49.55,0:09:52.04,Default,,0000,0000,0000,,because the genes\Nthat control behavior are complex.
Dialogue: 0,0:09:52.06,0:09:54.07,Default,,0000,0000,0000,,So if you're a terrorist\Nand have to choose
Dialogue: 0,0:09:54.10,0:09:56.45,Default,,0000,0000,0000,,between starting a grueling\Nbasic research program
Dialogue: 0,0:09:56.48,0:10:00.00,Default,,0000,0000,0000,,that will require years of meticulous\Nlab work and still might not pan out,
Dialogue: 0,0:10:00.03,0:10:01.38,Default,,0000,0000,0000,,or just blowing stuff up?
Dialogue: 0,0:10:01.40,0:10:03.06,Default,,0000,0000,0000,,You'll probably choose the later.
Dialogue: 0,0:10:03.50,0:10:05.92,Default,,0000,0000,0000,,This is especially true\Nbecause at least in theory,
Dialogue: 0,0:10:05.94,0:10:09.08,Default,,0000,0000,0000,,it should be pretty easy\Nto build what's called a reversal drive.
Dialogue: 0,0:10:09.10,0:10:12.80,Default,,0000,0000,0000,,That's one that basically overwrites\Nthe change made by the first gene drive.
Dialogue: 0,0:10:12.82,0:10:15.12,Default,,0000,0000,0000,,So if you don't like\Nthe effects of a change,
Dialogue: 0,0:10:15.14,0:10:17.97,Default,,0000,0000,0000,,you can just release a second drive\Nthat will cancel it out,
Dialogue: 0,0:10:17.100,0:10:19.15,Default,,0000,0000,0000,,at least in theory.
Dialogue: 0,0:10:21.37,0:10:23.10,Default,,0000,0000,0000,,OK, so where does this leave us?
Dialogue: 0,0:10:24.60,0:10:28.20,Default,,0000,0000,0000,,We now have the ability\Nto change entire species at will.
Dialogue: 0,0:10:29.02,0:10:30.18,Default,,0000,0000,0000,,Should we?
Dialogue: 0,0:10:30.55,0:10:31.92,Default,,0000,0000,0000,,Are we gods now?
Dialogue: 0,0:10:33.97,0:10:35.30,Default,,0000,0000,0000,,I'm not sure I'd say that.
Dialogue: 0,0:10:36.09,0:10:37.32,Default,,0000,0000,0000,,But I would say this:
Dialogue: 0,0:10:38.33,0:10:40.19,Default,,0000,0000,0000,,first, some very smart people
Dialogue: 0,0:10:40.21,0:10:43.07,Default,,0000,0000,0000,,are even now debating\Nhow to regulate gene drives.
Dialogue: 0,0:10:43.60,0:10:46.16,Default,,0000,0000,0000,,At the same time,\Nsome other very smart people
Dialogue: 0,0:10:46.19,0:10:48.30,Default,,0000,0000,0000,,are working hard to create safeguards,
Dialogue: 0,0:10:48.32,0:10:51.87,Default,,0000,0000,0000,,like gene drives that self-regulate\Nor peter out after a few generations.
Dialogue: 0,0:10:52.64,0:10:53.84,Default,,0000,0000,0000,,That's great.
Dialogue: 0,0:10:54.31,0:10:56.86,Default,,0000,0000,0000,,But this technology still requires\Na conversation.
Dialogue: 0,0:10:58.06,0:10:59.79,Default,,0000,0000,0000,,And given the nature of gene drives,
Dialogue: 0,0:10:59.81,0:11:01.50,Default,,0000,0000,0000,,that conversation has to be global.
Dialogue: 0,0:11:02.13,0:11:04.84,Default,,0000,0000,0000,,What if Kenya wants to use a drive\Nbut Tanzania doesn't?
Dialogue: 0,0:11:05.24,0:11:08.61,Default,,0000,0000,0000,,Who decides whether to release\Na gene drive that can fly?
Dialogue: 0,0:11:10.87,0:11:12.83,Default,,0000,0000,0000,,I don't have the answer to that question.
Dialogue: 0,0:11:13.62,0:11:15.63,Default,,0000,0000,0000,,All we can do going forward, I think,
Dialogue: 0,0:11:15.65,0:11:18.48,Default,,0000,0000,0000,,is talk honestly\Nabout the risks and benefits
Dialogue: 0,0:11:18.51,0:11:20.73,Default,,0000,0000,0000,,and take responsibility for our choices.
Dialogue: 0,0:11:21.82,0:11:25.73,Default,,0000,0000,0000,,By that I mean, not just the choice\Nto use a gene drive,
Dialogue: 0,0:11:25.75,0:11:27.75,Default,,0000,0000,0000,,but also the choice not to use one.
Dialogue: 0,0:11:29.11,0:11:32.09,Default,,0000,0000,0000,,Humans have a tendency to assume\Nthat the safest option
Dialogue: 0,0:11:32.11,0:11:33.90,Default,,0000,0000,0000,,is to preserve the status quo.
Dialogue: 0,0:11:34.90,0:11:36.48,Default,,0000,0000,0000,,But that's not always the case.
Dialogue: 0,0:11:37.71,0:11:41.11,Default,,0000,0000,0000,,Gene drives have risks,\Nand those need to be discussed,
Dialogue: 0,0:11:41.14,0:11:44.29,Default,,0000,0000,0000,,but malaria exists now\Nand kills 1,000 people a day.
Dialogue: 0,0:11:44.98,0:11:48.54,Default,,0000,0000,0000,,To combat it, we spray pesticides\Nthat do grave damage to other species,
Dialogue: 0,0:11:48.56,0:11:50.14,Default,,0000,0000,0000,,including amphibians and birds.
Dialogue: 0,0:11:51.67,0:11:54.53,Default,,0000,0000,0000,,So when you hear about gene drives\Nin the coming months,
Dialogue: 0,0:11:54.56,0:11:56.81,Default,,0000,0000,0000,,and trust me, you will\Nbe hearing about them,
Dialogue: 0,0:11:56.83,0:11:58.38,Default,,0000,0000,0000,,remember that.
Dialogue: 0,0:11:58.40,0:12:00.42,Default,,0000,0000,0000,,It can be frightening to act,
Dialogue: 0,0:12:00.45,0:12:02.58,Default,,0000,0000,0000,,but sometimes, not acting is worse.
Dialogue: 0,0:12:04.75,0:12:12.57,Default,,0000,0000,0000,,(Applause)