WEBVTT - How do we control mosquito populations? 0:00:09.200 --> 0:00:11.639 If you live in most places in the United States, 0:00:11.720 --> 0:00:14.160 mosquitoes are a massive annoyance. 0:00:14.520 --> 0:00:16.400 They've ruined a good hike, They've ruined a. 0:00:16.320 --> 0:00:20.080 Beautiful night camping under the stars, They've ruined delicious picnics, 0:00:20.320 --> 0:00:22.520 and they've ruin breathtaking sunsets. 0:00:23.320 --> 0:00:25.520 They are the worst. 0:00:25.800 --> 0:00:28.520 But if you live in an area where mosquitos carry 0:00:28.520 --> 0:00:33.200 deadly diseases like malaria, dengey, yellow fever, or zeka, they're 0:00:33.320 --> 0:00:37.040 also potentially deadly. According to the Centers for Disease Control, 0:00:37.240 --> 0:00:41.600 malaria alone killed five hundred and ninety seven thousand people 0:00:41.720 --> 0:00:42.720 in twenty twenty three. 0:00:43.520 --> 0:00:44.639 So what are our options. 0:00:45.600 --> 0:00:49.919 Mosquitoes have developed resistance to our insecticides, and insecticides in 0:00:49.960 --> 0:00:53.000 general aren't great for ecosystems because they often kill a 0:00:53.000 --> 0:00:55.360 bunch of other stuff as well. But what if we 0:00:55.400 --> 0:00:59.560 could use new genetic tools to drive some mosquito species 0:00:59.560 --> 0:01:03.480 to extend or make those mosquitoes resistant to diseases so 0:01:03.520 --> 0:01:07.840 they can no longer transmit those diseases to us. Today, 0:01:07.920 --> 0:01:10.559 we're going to respond to some listener questions about mosquitoes. 0:01:10.880 --> 0:01:14.360 We'll chat about how mosquitoes find us, how genetic engineering 0:01:14.400 --> 0:01:17.480 could be used to combat mosquitoes and how you undertake 0:01:17.520 --> 0:01:21.920 the tricky task of estimating how mosquito population sizes are 0:01:22.040 --> 0:01:28.160 changing over time. Welcome to Daniel and Kelly's Mosquito Infested Universe. 0:01:41.400 --> 0:01:41.600 Hi. 0:01:41.720 --> 0:01:44.480 I'm Daniel. I'm a particle physicist, and I have a 0:01:44.640 --> 0:01:47.640 top five list of animals i'd like to see genocided 0:01:47.680 --> 0:01:48.240 off the planet. 0:01:48.360 --> 0:01:51.480 Oh Man starting an episode with the word genocide. 0:01:52.160 --> 0:01:54.320 Not loving that. Hi, I'm Kelly Waiter Smith. 0:01:54.520 --> 0:01:56.640 I study parasites and space, and I was going to 0:01:56.680 --> 0:02:00.640 say I'm buzzing with enthusiasm for this topic, but Daniel 0:02:00.720 --> 0:02:04.000 started with genocides, So my enthusiasm has been shot through. 0:02:04.520 --> 0:02:08.000 Did that sting you a little bit? Scratching the wrong 0:02:08.040 --> 0:02:08.679 itch over there? 0:02:09.080 --> 0:02:12.000 I can't, I can't, I can't. All right, what are 0:02:12.040 --> 0:02:15.480 the five insects that you like the least, Daniel? We 0:02:15.480 --> 0:02:16.680 could put it that way too, you know. 0:02:16.880 --> 0:02:21.720 Yeah, number five mosquitoes, Number four mosquitoes, number three mosquitoes, 0:02:21.840 --> 0:02:24.880 number two mosquitoes, and number one coming in at the 0:02:24.880 --> 0:02:27.679 top of the list is mosquito. 0:02:27.760 --> 0:02:31.959 Yes, predictable list. Yeah. I'm not a mosquito fan really either. 0:02:31.840 --> 0:02:35.120 Absolutely, And so I'm fascinated today that we're going to 0:02:35.160 --> 0:02:38.360 be talking about the science of mosquitoes and learning about 0:02:38.680 --> 0:02:42.520 everything that biologists can do to improve our quality of life. 0:02:42.680 --> 0:02:46.120 Yeah, I'm a biologists and engineers. A variety of folks 0:02:46.160 --> 0:02:49.480 for many decades have been trying to do battle with mosquitoes, 0:02:49.639 --> 0:02:51.320 and you know, in the last few decades, we now 0:02:51.320 --> 0:02:54.680 have some genetic tools that we can use that might give. 0:02:54.520 --> 0:02:55.200 Us the leg up. 0:02:55.360 --> 0:02:59.120 And your focus, of course, is on eradicating disease, caring 0:02:59.160 --> 0:03:01.800 mosquitoes because that kills people and all that stuff and 0:03:02.040 --> 0:03:05.760 that along the way. Along the way, I would to 0:03:05.800 --> 0:03:10.960 eradicate Daniel's suffering from mosquito bites, because that's what it's 0:03:11.000 --> 0:03:12.560 really all about. In the end, It's about me and 0:03:12.600 --> 0:03:13.359 my itches. 0:03:13.120 --> 0:03:19.400 Right, No, i'd say no, Yeah, I don't actually know that. 0:03:19.480 --> 0:03:23.000 I would advocate for eliminating mosquitoes that are annoying but 0:03:23.080 --> 0:03:26.000 don't transmit disease, although I guess in California do do 0:03:26.080 --> 0:03:27.560 your mosquitoes transmit Wes Nile? 0:03:27.880 --> 0:03:30.600 I don't know. I have heard of cases, but I'm 0:03:30.600 --> 0:03:33.640 not sure. But really, for me, it's just all about 0:03:33.639 --> 0:03:36.200 the itches. I'm not a great sleeper and I'm very 0:03:36.240 --> 0:03:38.600 responsive to mosquito bites, which means if I get too 0:03:38.640 --> 0:03:41.400 many mosquito bites, then I'm up all nights scratching them. 0:03:41.840 --> 0:03:45.600 So it's really a bummer. I would happily actually donate 0:03:45.640 --> 0:03:48.200 my blood to the mosquitoes if we could make a deal, 0:03:48.640 --> 0:03:50.480 like if I could just put out a little like 0:03:50.600 --> 0:03:52.640 saucer of blood every night and be like, here's your 0:03:52.680 --> 0:03:55.640 blood meal, leave me alone. I would make that deal 0:03:55.920 --> 0:03:59.000 no trouble at all. So if the mosquito's lawyer wants 0:03:59.040 --> 0:04:00.600 to reach out and to go she ates some sort 0:04:00.600 --> 0:04:03.000 of settlement like that, I am open for business. 0:04:03.200 --> 0:04:05.680 All yes, So you give your fecal sample to your 0:04:05.720 --> 0:04:08.360 wife and your blood sample to the mosquitoes. 0:04:08.840 --> 0:04:10.280 Everybody needs a part of Daniel. 0:04:10.600 --> 0:04:13.920 Come take a sample exactly. Matt will take an audio sample. 0:04:14.000 --> 0:04:14.480 Here we go. 0:04:15.320 --> 0:04:15.760 All right. 0:04:16.200 --> 0:04:18.719 Well, then you will be very excited to hear today 0:04:18.720 --> 0:04:21.159 that there are a variety of cutting edge techniques for 0:04:22.200 --> 0:04:25.640 in some cases straight up eradicating mosquitos and in other 0:04:25.680 --> 0:04:27.359 cases just trying to make it so that they can't 0:04:27.400 --> 0:04:28.520 carry disease anymore. 0:04:29.040 --> 0:04:30.800 I like the sound a straight up eradication. 0:04:31.720 --> 0:04:37.120 Well, I reached out to our extraordinaries and asked them 0:04:37.320 --> 0:04:40.880 what they think the most promising techniques for eradicating disease 0:04:40.920 --> 0:04:43.279 carrying mosquitoes are and let's go ahead and hear what 0:04:43.320 --> 0:04:45.080 they had to say, treat. 0:04:44.880 --> 0:04:47.120 The water where they breed, kill the larvae. 0:04:47.279 --> 0:04:49.839 Someone far smarter than I am must have a technique 0:04:49.880 --> 0:04:52.120 to get them to stop breeding. I like what they've 0:04:52.160 --> 0:04:55.640 done in the past with releasing genetically modified ones so 0:04:55.680 --> 0:04:59.839 that it reduces the population and potentially targets those disease 0:05:00.040 --> 0:05:04.839 carrying ones, because the generic sprays kill all sorts of 0:05:04.880 --> 0:05:07.880 insects and they are beneficial for the ecosystem. 0:05:08.240 --> 0:05:12.360 Does the Geneva convention apply to mosquitoes? That does, I'd 0:05:12.360 --> 0:05:17.440 have to say some bioengineered aerosol that wouldn't harm other 0:05:18.240 --> 0:05:19.120 living creatures. 0:05:19.200 --> 0:05:23.040 The one technique I know right now is that some 0:05:23.160 --> 0:05:27.160 larvacide is spread during mosquito season. I'm not so sure 0:05:27.240 --> 0:05:30.200 that is the most promising technique, since that's been done 0:05:30.240 --> 0:05:31.880 for a long time and we still get a lot 0:05:31.920 --> 0:05:32.560 of mosquitos. 0:05:32.760 --> 0:05:35.920 It appears the sterile insect technique is the most promising method, 0:05:36.080 --> 0:05:38.400 though I'm not sure if that will eradicate or just 0:05:38.560 --> 0:05:41.800 vastly reduce population numbers, and is nowhere near as fun 0:05:41.839 --> 0:05:43.480 as an electrified racket swater. 0:05:43.800 --> 0:05:48.280 We would genetically engineer some very attractive but sterile mosquitos, 0:05:48.839 --> 0:05:53.360 dispatch them two the affected areas. Let dat run its course, 0:05:54.080 --> 0:05:57.479 and over time the population will fade away. 0:05:57.440 --> 0:05:59.640 Do the thing they're doing with the screw worms and 0:05:59.680 --> 0:06:02.839 doing like sterilized ones. And I really do hope that 0:06:02.920 --> 0:06:05.480 you kill all mosquitos, because they love me. I am 0:06:05.520 --> 0:06:07.960 foreign food here in the UK, even though I'm havy English, 0:06:08.120 --> 0:06:09.440 So kill them all. 0:06:09.920 --> 0:06:11.520 I think a lot of people are on the same 0:06:11.520 --> 0:06:14.159 page with you, Daniel eradicating mosquitos. 0:06:14.200 --> 0:06:15.240 They are on board. 0:06:15.520 --> 0:06:17.679 It sounds like somebody else spoke to the mosquito's lawyer 0:06:17.720 --> 0:06:21.080 because they're referencing the Geneva Convention and like getting illegal 0:06:21.120 --> 0:06:22.360 about it. Oh my gosh. 0:06:22.560 --> 0:06:25.080 I know, I know these things are intense well. And 0:06:25.240 --> 0:06:26.960 you know, in the United States, if you do want 0:06:27.000 --> 0:06:30.640 to release some method for eradicating mosquitos, you do need 0:06:30.680 --> 0:06:33.560 to go through like the USDA, the EPA. We'll talk 0:06:33.600 --> 0:06:35.560 about this a little bit more later. There's some legal 0:06:35.600 --> 0:06:36.279 stuff involved. 0:06:36.360 --> 0:06:39.040 I think that probably makes sense. Somebody should think about 0:06:39.040 --> 0:06:41.760 whether these are good ideas before we just like let 0:06:41.880 --> 0:06:44.480 scientists do things. Willy nilly, I'm for that. 0:06:44.800 --> 0:06:47.320 I'm gonna let you in on a little secret. We've 0:06:47.320 --> 0:06:49.599 messed things up a few times in the past. 0:06:49.680 --> 0:06:50.720 Yeah, I know, I know. 0:06:50.839 --> 0:06:53.359 Right now, we can't be trusted to make our own decisions. 0:06:53.440 --> 0:06:56.120 Well, I think some oversight is warranted. 0:06:56.720 --> 0:06:57.720 That's a good way to put it. 0:06:57.760 --> 0:06:59.560 We get a little over enthusiastic. 0:07:00.040 --> 0:07:03.320 Yeah, we knew because the universe is amazing and we 0:07:03.400 --> 0:07:05.160 just want to learn stuff and we think we have 0:07:05.240 --> 0:07:07.320 it figured out, and so yeah, we just want to 0:07:07.320 --> 0:07:08.920 press the big red button sometimes. 0:07:09.120 --> 0:07:11.760 Well, today we're going to be learning specifically about answers 0:07:11.760 --> 0:07:14.600 to questions that we got from listeners. And we called 0:07:14.640 --> 0:07:18.080 in a little bit of backup because any biology topic 0:07:18.160 --> 0:07:22.080 is improved by having Katrina Whiteson join the podcast. So 0:07:22.680 --> 0:07:24.239 let's invite Katrina on the show. 0:07:24.560 --> 0:07:27.320 It's my great pleasure to welcome back to the podcast, 0:07:27.440 --> 0:07:30.560 our most popular, our most frequent guest, also winner of 0:07:30.600 --> 0:07:32.760 the whites In Unable to Say No To a Podcast 0:07:32.880 --> 0:07:36.560 Invitation Award, doctor and Professor Katrina Whitson. 0:07:37.000 --> 0:07:40.000 Wow, thank you for the glamorous introduction. 0:07:43.960 --> 0:07:45.760 Thank you for being willing to come back on the 0:07:45.800 --> 0:07:47.400 show again. We always love having you. 0:07:47.640 --> 0:07:52.160 Well. Thanks all around, all right. 0:07:52.480 --> 0:07:53.360 Let's dive right in. 0:07:53.760 --> 0:07:57.160 So we have a couple questions from Robert Shackelford, who 0:07:57.240 --> 0:07:59.720 is a high school teacher who wanted to know about mosquito. 0:08:00.120 --> 0:08:00.920 Let's dive in. 0:08:01.400 --> 0:08:04.240 Hello, Daniel and Kelly, this is Robert on Samun Island 0:08:04.280 --> 0:08:08.400 in Washington State. And I'm curious about mosquitoes. Well, it's 0:08:08.400 --> 0:08:10.640 probably more accurate to say they seem to be curious 0:08:10.640 --> 0:08:14.520 about me, unfortunately. And where we live there's a pond nearby, 0:08:15.040 --> 0:08:18.240 and if you're anywhere near the pond, you will get 0:08:18.280 --> 0:08:21.280 bidden right away. Further from the pond, it's not so 0:08:21.480 --> 0:08:24.640 bad unless you're stationary, and then they will find you. 0:08:24.720 --> 0:08:27.520 And when they find you, they really find you. And 0:08:27.560 --> 0:08:32.040 that has me wondering if they are coordinating their attack somehow, 0:08:32.760 --> 0:08:36.280 if they are watching each other, or if they are 0:08:36.320 --> 0:08:39.320 our little mosquito walkie talkies I don't know, or they're 0:08:39.320 --> 0:08:44.040 just acting individually on the same clues to find the victim. 0:08:44.360 --> 0:08:47.760 And then similarly, I would love to know how many 0:08:47.800 --> 0:08:50.360 mosquitoes I'm up against, right, it's important. 0:08:49.960 --> 0:08:50.800 To know your enemy. 0:08:51.640 --> 0:08:56.680 And how would you ever estimate a mosquito population? I 0:08:56.720 --> 0:09:01.680 know there's some techniques for estimating wildlife, say birds, by 0:09:01.760 --> 0:09:05.400 tagging them and then recapturing them later, But I can 0:09:05.520 --> 0:09:09.200 imagine doing that with mosquitos. Sorry, Kelly, I can't imagine 0:09:09.200 --> 0:09:13.439 even the best biologist having the ability to take little 0:09:13.440 --> 0:09:16.040 tag number forty two and glue it to a mosquito's 0:09:16.080 --> 0:09:19.280 leg and be able to capture it later. So I'm curious. 0:09:19.400 --> 0:09:22.160 Is there a way Is that number even that knowable? 0:09:22.320 --> 0:09:23.839 Is there a way to make a good estimate of 0:09:23.920 --> 0:09:28.079 mosquito population? Really curious? Thank you so much for taking 0:09:28.080 --> 0:09:30.400 on my question. Look forward to hearing from you soon. 0:09:30.960 --> 0:09:34.000 Wonderful question. I love hearing from high school teachers, and 0:09:34.040 --> 0:09:36.400 thank you to all the teachers out there working on 0:09:36.440 --> 0:09:39.360 the front lines of education to make society a better 0:09:39.360 --> 0:09:40.600 place than everybody smarter. 0:09:40.840 --> 0:09:41.640 You all are heroes. 0:09:41.679 --> 0:09:45.160 Thank you so much, And I am thrilled to get 0:09:45.200 --> 0:09:48.439 to educate folks about mosquitos, which I have to admit 0:09:48.520 --> 0:09:48.920 I hate. 0:09:49.120 --> 0:09:51.880 It's not hard to admit you hate mosquitos. It's joyful. 0:09:52.160 --> 0:09:54.400 I guess don't know how many collegist I'm supposed to 0:09:54.440 --> 0:09:57.040 like almost everything, but I have to admit dipterines, which 0:09:57.040 --> 0:09:59.760 are like mosquitos and flies, I'm not a big fan 0:09:59.840 --> 0:10:00.440 of well. 0:10:00.480 --> 0:10:01.840 You know, I used to say all the time that 0:10:02.000 --> 0:10:05.120 mosquitos are the one thing you could like erase from 0:10:05.160 --> 0:10:07.319 the planet and not have any negative effects. But then 0:10:07.360 --> 0:10:10.520 some listeners sent me an article about how mosquitos helped 0:10:10.679 --> 0:10:14.880 chocolate help cocoa beans pollinate each other, and I was like, uh, oh, 0:10:15.080 --> 0:10:17.360 I'm not sure if I had to give up mosquitos 0:10:17.360 --> 0:10:18.880 if I would also give up chocolate. 0:10:19.840 --> 0:10:21.640 It sounds a little bit tough at first, but when 0:10:21.679 --> 0:10:26.080 you consider that mosquitoes transmit malaria, which kills almost six 0:10:26.160 --> 0:10:29.400 hundred thousand people a year, I would give up chocolate 0:10:29.440 --> 0:10:29.640 for that. 0:10:30.640 --> 0:10:33.280 I mean, I hear you, But we're talking about chocolate here, Kelly. 0:10:33.440 --> 0:10:35.080 We're talking about children, Daniel. 0:10:35.120 --> 0:10:37.760 But I have to remember that you are willing to 0:10:37.760 --> 0:10:40.080 give up all of humanity to get one answer from 0:10:40.080 --> 0:10:40.600 an alien. 0:10:40.840 --> 0:10:41.800 We had that discussion the. 0:10:41.800 --> 0:10:44.960 Other that juicy answer. But yes, yes, I am, that's true, 0:10:45.000 --> 0:10:45.440 all right. 0:10:45.520 --> 0:10:47.959 I'll note that his wife was also shaking her head 0:10:48.000 --> 0:10:48.720 in disbelief. 0:10:50.679 --> 0:10:52.880 I don't like this new number of podcast hosts where 0:10:52.880 --> 0:10:53.800 I can get outvoted. 0:10:55.679 --> 0:10:57.720 We'll go back to mosquitoes. 0:10:58.720 --> 0:11:02.160 Mosquitos are often enlisted as the deadliest animals on the 0:11:02.200 --> 0:11:05.319 planet Wow. And one of the problems caused by mosquitos 0:11:05.400 --> 0:11:08.640 is that they transmit malaria. There are over five hundred 0:11:08.679 --> 0:11:12.440 Anoplies mosquito species, so this is like a genus of mosquito, 0:11:12.760 --> 0:11:16.320 and about sixty of those species are able to transmit malaria. 0:11:16.960 --> 0:11:22.440 Mosquitos also transmit Dangae west Niles zega lymphatic philoriasis, and 0:11:22.520 --> 0:11:26.640 so mosquitoes are estimated to kill indirectly up to a 0:11:26.760 --> 0:11:29.960 million people a year. But I've never felt like this 0:11:30.000 --> 0:11:32.640 is super fair to pin on mosquitos, even though I 0:11:32.640 --> 0:11:37.000 hate mosquitoes, because it's like, isn't it the individual responsibility 0:11:37.000 --> 0:11:41.240 of all of those diseases. It's not necessarily the mosquitoes. 0:11:41.440 --> 0:11:43.280 But I get I get it. 0:11:43.400 --> 0:11:46.640 They were unwilling partners. Nobody like, they didn't say, yeah, 0:11:46.760 --> 0:11:49.679 bring on that plasmodium. They were just like flying a rods. 0:11:50.600 --> 0:11:52.880 But they do drink blood. I mean, I don't know. 0:11:53.000 --> 0:11:54.640 I mean, Kelly, if I came over to your house 0:11:54.679 --> 0:11:56.840 and drank your blood and give you some weird disease, 0:11:56.960 --> 0:11:59.559 I think you'd blame me for anything you got, wouldn't you? 0:11:59.559 --> 0:12:02.920 You wouldn't be invited again. That's true. 0:12:03.880 --> 0:12:05.920 And you would be breaking a lot of social wars 0:12:06.000 --> 0:12:08.640 to do that, and laws and laws and laws. Right, 0:12:08.880 --> 0:12:11.680 But does anybody want to guess? This surprised me a little, 0:12:11.679 --> 0:12:15.480 But it shouldn't have. On the list of species that 0:12:15.559 --> 0:12:19.960 kill humans, mosquitoes are at the top. What species is second? 0:12:20.280 --> 0:12:24.679 The next most killing e species kills about half as 0:12:24.720 --> 0:12:26.880 many humans each year. But what would you guess? That 0:12:26.920 --> 0:12:27.600 species is? 0:12:28.040 --> 0:12:33.839 Raccoons? Those are ferocious? Have you heard that story about raccoons? 0:12:34.320 --> 0:12:37.560 Don't have a pet raccoon? FYI, and don't google what 0:12:37.640 --> 0:12:39.720 happens if you lead a raccoon in a room with 0:12:39.760 --> 0:12:40.200 your baby. 0:12:40.280 --> 0:12:41.520 Oh, definitely don't google that. 0:12:41.720 --> 0:12:45.199 But I would guess it's microbial. I mean, it has 0:12:45.240 --> 0:12:48.439 to be microbial. Microbes rule the world. So now I've 0:12:48.480 --> 0:12:51.080 got to like pick from microbes, and I really should 0:12:51.200 --> 0:12:51.400 know this. 0:12:51.760 --> 0:12:54.200 I mean, it could be tuberculosis. 0:12:53.360 --> 0:12:56.679 Bacteria that is still a problem which. 0:12:56.440 --> 0:13:00.760 Infects a third of humans. Or it could be real raccoons, 0:13:00.840 --> 0:13:01.640 my gosh. 0:13:01.520 --> 0:13:04.800 Some kind of parasite, some kind of eukaryotic parasite. 0:13:04.840 --> 0:13:05.400 Is that what it is? 0:13:06.800 --> 0:13:07.480 It's humans? 0:13:07.679 --> 0:13:09.000 Oh my god? 0:13:09.000 --> 0:13:10.360 Oh that's so good. 0:13:10.720 --> 0:13:14.080 I think Katrina gets points because we are eukaryotic parasites, right, 0:13:14.120 --> 0:13:15.120 So there you go. 0:13:15.280 --> 0:13:17.920 There you go point So Katrina essentially got it right. 0:13:18.160 --> 0:13:21.439 One point for Katrina, zero points for raccoons. 0:13:21.480 --> 0:13:24.480 From Daniel, I'm not gonna I can't take any points. 0:13:24.520 --> 0:13:26.760 I was going down a totally wrong road there, and 0:13:26.960 --> 0:13:28.920 I really thought it was my crogial, you know. 0:13:29.120 --> 0:13:31.680 I also felt like you could just blame bacteria across 0:13:31.760 --> 0:13:34.280 the board. But anyway, the list right now has humans. 0:13:34.600 --> 0:13:37.120 I guess we kill about half a million of each 0:13:37.200 --> 0:13:39.680 other every year, which is depressing. 0:13:39.880 --> 0:13:40.240 Wow. 0:13:40.600 --> 0:13:42.480 But all right, let's talk about the mosquito life cycle 0:13:42.480 --> 0:13:45.000 real quick, because understanding the life cycle is necessary if 0:13:45.000 --> 0:13:47.600 you're going to understand how you can try to eradicate 0:13:47.640 --> 0:13:49.600 mosquitos by breaking part of the life cycle. 0:13:50.080 --> 0:13:51.679 So first, let's note. 0:13:51.480 --> 0:13:55.160 There's lots of mosquito species, like over three thousand, five 0:13:55.240 --> 0:13:59.480 hundred mosquito species. They don't all bite humans. The ones 0:13:59.520 --> 0:14:03.040 that you bite humans are females. The males actually don't 0:14:03.080 --> 0:14:06.199 take blood meals, and the females apparently need the blood 0:14:06.280 --> 0:14:10.040 to make eggs. Okay, so if you get bit it's 0:14:10.080 --> 0:14:12.160 a female, don't blame the female. They're just doing what 0:14:12.200 --> 0:14:14.599 evolution made them. Do but anyway, so they do the 0:14:14.640 --> 0:14:16.719 blood meal. So they get a blood meal, they lay 0:14:16.760 --> 0:14:20.200 their eggs in a body of water, the eggs hatch 0:14:20.200 --> 0:14:22.480 in the water, and then they've got this aquatic stage 0:14:22.520 --> 0:14:25.480 where they look like these sort of like frilly little 0:14:25.720 --> 0:14:29.080 specks of dirt that kind of move around like crazy 0:14:29.080 --> 0:14:30.880 all over the place. Sometimes you might see them in 0:14:30.920 --> 0:14:33.400 like a bird feeder in the middle of the summer 0:14:33.520 --> 0:14:36.120 or something. And then they have another stage where they 0:14:36.200 --> 0:14:38.320 essentially like stay near the surface and they're kind of 0:14:38.320 --> 0:14:42.080 getting oxygen from the surface. And then they emerge out 0:14:42.080 --> 0:14:45.200 of the aquatic environment as adults and they go off 0:14:45.280 --> 0:14:47.200 and you know, mate with each other and go off 0:14:47.200 --> 0:14:47.920 in search of blood. 0:14:48.040 --> 0:14:50.240 And all this happens in hours or days. 0:14:50.040 --> 0:14:52.480 Or depends on the species. There's a lot of variability, 0:14:52.480 --> 0:14:54.720 but an egg can take something like seven to ten 0:14:54.840 --> 0:14:57.440 days to develop into an adult, and then when they're 0:14:57.440 --> 0:14:59.600 an adult, I think they've got like a week or 0:14:59.680 --> 0:15:01.800 a few weeks. They don't live for very long, so. 0:15:01.800 --> 0:15:03.840 When a mosquito is biting you, it's like one of 0:15:03.920 --> 0:15:06.680 a few dozen meals it's gonna have in its lifetime, 0:15:07.280 --> 0:15:09.400 or how many blood meals does a mosquito have in 0:15:09.440 --> 0:15:10.440 their whole lifetime. 0:15:10.680 --> 0:15:13.040 They must be taking more than one blood meal. But 0:15:13.280 --> 0:15:15.920 I think they only mate with a male once in 0:15:15.960 --> 0:15:19.520 their life and lay eggs once, and that has to 0:15:19.560 --> 0:15:21.240 be the case for a bunch of the techniques that 0:15:21.280 --> 0:15:22.760 we talk about later to work. 0:15:23.080 --> 0:15:24.800 Well. I know that in southern California we have two 0:15:24.800 --> 0:15:26.800 different kinds of mosquitos. So the ones that come and 0:15:26.840 --> 0:15:29.720 give you one really big juicy bite and then move on, 0:15:30.160 --> 0:15:32.240 and another tiny version that come in bye you like 0:15:32.240 --> 0:15:33.400 four times in a row. 0:15:33.800 --> 0:15:35.080 Oh they're all awful. 0:15:35.120 --> 0:15:36.320 Though, they're all awful. 0:15:36.480 --> 0:15:39.480 Yeah, thumbs down. Well, so then how do they find you? 0:15:40.000 --> 0:15:43.560 So Robert wanted to know if they're like communicating with 0:15:43.600 --> 0:15:45.920 each other so that they can swarm and get to you, 0:15:46.440 --> 0:15:48.640 and I don't think that that's what's happening. I didn't 0:15:48.640 --> 0:15:51.800 find any evidence that a mosquito is like altruistic enough 0:15:51.800 --> 0:15:54.920 to be like, hey, there's a snack over here, fellas, 0:15:55.160 --> 0:15:58.080 or I guess, ladies, Hey, ladies, there's a snack over here, 0:15:58.200 --> 0:16:00.720 because it's all females do in the feeding. I think 0:16:00.720 --> 0:16:03.400 that the only times they swarm on purpose is when 0:16:03.440 --> 0:16:06.880 they're trying to mate, and so usually they're not sharing information. 0:16:06.960 --> 0:16:10.120 But the way they find you is a multi step process. First, 0:16:10.200 --> 0:16:13.760 they detect the carbon dioxide that we breathe out, and 0:16:13.800 --> 0:16:16.680 then they follow the carbon dioxide trail until they get 0:16:16.680 --> 0:16:19.560 close to us. When they start getting close enough to us, 0:16:19.560 --> 0:16:21.960 they start detecting some odors that we give off. And 0:16:22.000 --> 0:16:26.000 these odors can be things like ketones, lactic acids, and Katrina, 0:16:26.040 --> 0:16:27.680 I read that a lot of the odors we give 0:16:27.720 --> 0:16:30.479 off are related to our microbiome exactly. 0:16:30.560 --> 0:16:32.920 I even had a whole grant once. I didn't get it, 0:16:32.920 --> 0:16:34.880 but I wrote a grant with a bunch of people. 0:16:35.480 --> 0:16:37.680 It was a military grant, and the goal was to 0:16:37.800 --> 0:16:40.640 make soldiers invisible to mosquitoes. And you're going to do 0:16:40.680 --> 0:16:43.400 it by changing their skin microbiomes. And you know, some 0:16:43.480 --> 0:16:46.720 people are just so juicy to mosquitos and they get 0:16:46.760 --> 0:16:49.800 bitten all the time and others don't. And we don't 0:16:49.840 --> 0:16:52.560 know why really, but I think it could be related 0:16:52.600 --> 0:16:55.360 to the microbiome and the volatiles that the microbes are 0:16:55.360 --> 0:16:59.160 emitting that the mosquitoes can detect, and so anyway, it 0:16:59.240 --> 0:17:01.200 might be that that's something we can change. 0:17:01.240 --> 0:17:02.360 Like, that's pretty amazing. 0:17:02.560 --> 0:17:04.480 Hold on a second, I just put two and two together. 0:17:04.920 --> 0:17:06.560 I live in a house where I'm the one getting 0:17:06.600 --> 0:17:09.640 bitten by mosquitoes all the time, and I also live 0:17:09.640 --> 0:17:13.159 in a house where somebody knows how to manipulate people's microbiomes. 0:17:13.560 --> 0:17:16.000 And I just heard that microbiomes are the number one 0:17:16.040 --> 0:17:21.160 influence and who gets bitten by mosquitoes? Hmm, Okay, I'm 0:17:21.160 --> 0:17:22.160 gonna have to think about that. 0:17:22.240 --> 0:17:26.080 Okay, This mosquito preference thing has been going on since 0:17:26.200 --> 0:17:28.359 way before I learned about microbiomes. 0:17:30.359 --> 0:17:32.119 I see, so you've been guilty for a long time, 0:17:32.280 --> 0:17:34.000 got it, got it all right? 0:17:34.200 --> 0:17:35.400 But it could be a life goal. 0:17:35.760 --> 0:17:38.679 But for the individual mosquito, Kelly, this is not, like 0:17:39.119 --> 0:17:41.840 you know, they have complicated sensors. I'm imagining they're like 0:17:41.880 --> 0:17:44.280 flying through the air and they sort of veer towards 0:17:44.280 --> 0:17:46.560 the CO two instead of away from it. It's sort 0:17:46.560 --> 0:17:48.560 of like moths being attracted to light. Is that how 0:17:48.560 --> 0:17:48.960 it works? 0:17:49.200 --> 0:17:49.400 Yeah? 0:17:49.560 --> 0:17:51.320 I mean I think it might be under selling it 0:17:51.359 --> 0:17:53.800 a little bit to say that they don't have complicated sensors. 0:17:53.800 --> 0:17:55.840 So like moths, for example, the males who have to 0:17:55.920 --> 0:17:59.480 find the females, they have super feathery antenna and nobody 0:17:59.520 --> 0:17:59.840 can see. 0:17:59.880 --> 0:18:02.040 But I have hand antennas right now. 0:18:02.160 --> 0:18:03.760 You're looking very mathia, I thank. 0:18:03.640 --> 0:18:04.159 You, thank you. 0:18:04.400 --> 0:18:08.080 And they, you know, have an incredible surface area, and 0:18:08.080 --> 0:18:10.800 they're able to detect chemicals that the females put into 0:18:10.840 --> 0:18:13.800 the environment and follow that chemical trail to find a female. 0:18:14.280 --> 0:18:16.520 And so, you know, like insects, they you know, they 0:18:16.600 --> 0:18:19.080 might not look super impressive, but they do have pretty 0:18:19.119 --> 0:18:22.199 impressive ways of detecting cues in the environment. Like I 0:18:22.240 --> 0:18:24.919 can't detect CO two and use it to find my 0:18:25.040 --> 0:18:26.960 dog when she's not coming in the middle of the 0:18:27.040 --> 0:18:30.440 night when I call her. So anyway, I'm impressed. But yeah, 0:18:30.600 --> 0:18:31.919 it's not super complicated. 0:18:32.040 --> 0:18:33.800 I mean, I think there's a lot of sensors that 0:18:33.840 --> 0:18:36.159 we actually don't know what they are. That's something that 0:18:36.240 --> 0:18:39.520 I'm so fascinated by that apparently, you know, we have 0:18:39.600 --> 0:18:42.800 these sensory receptors that we know about in our nose 0:18:42.800 --> 0:18:44.760 and our tongue, like you hear about the sense of taste, 0:18:44.800 --> 0:18:47.760 But actually we have those kind of receptors all. 0:18:47.600 --> 0:18:48.200 Over the place. 0:18:48.240 --> 0:18:50.600 They're in our skin, they're in our guts, like babies 0:18:50.640 --> 0:18:53.720 have them when they're developing, and so I think those 0:18:53.960 --> 0:18:56.760 receptors are binding molecules we don't even know what they 0:18:56.760 --> 0:18:59.160 are yet, and I would not be surprised the mosquitoes 0:18:59.200 --> 0:18:59.960 have a lot of that going on. 0:19:00.480 --> 0:19:02.439 You're saying we can taste with our hands and stuff 0:19:02.480 --> 0:19:05.320 like that, exactly. I see. So when I swat a 0:19:05.359 --> 0:19:08.119 mosquito and I feel that like moment of satisfaction, it's like, 0:19:08.240 --> 0:19:09.240 literally delicious. 0:19:09.840 --> 0:19:11.160 Let me just back up on that. 0:19:11.240 --> 0:19:14.399 I'm saying, there's receptors that are sensing those molecules and 0:19:14.440 --> 0:19:18.239 you're having a response. The response is not lighting up 0:19:18.280 --> 0:19:20.440 the taste receptors in your brain, at least. 0:19:20.240 --> 0:19:20.639 Not for me. 0:19:20.880 --> 0:19:24.920 I mean, I don't know about you, but I think 0:19:24.960 --> 0:19:28.480 it's like lighting up something that not necessarily that we're 0:19:28.480 --> 0:19:30.480 even aware of it in our brain, but it could 0:19:30.480 --> 0:19:32.000 be like affecting our physiology. 0:19:32.119 --> 0:19:32.359 You know. 0:19:32.440 --> 0:19:34.480 We had Stephen Munger on the show to talk about 0:19:34.520 --> 0:19:36.280 taste and smell, and he was talking about how we 0:19:36.280 --> 0:19:39.000 have receptors for things like even in our hearts, and 0:19:39.040 --> 0:19:40.639 it's not quite clear why we have them. So if 0:19:40.640 --> 0:19:42.680 folks want to learn more about that, they should check 0:19:42.680 --> 0:19:45.080 out the Manger episode because we talk about that for 0:19:45.119 --> 0:19:47.320 a little bit. It's totally fascinating in my opinion. 0:19:47.640 --> 0:19:49.720 All Right, so, but we were talking about how mosquitoes 0:19:49.760 --> 0:19:51.679 find hosts, and you're saying, at first they look for 0:19:51.720 --> 0:19:54.360 clouds of CO two, and then as they get closer, 0:19:54.400 --> 0:19:57.359 they're looking for skin odorans that give them cues to 0:19:57.400 --> 0:20:00.200 where you are, and then what walk us through through 0:20:00.240 --> 0:20:01.360 all the way to the bite. 0:20:01.440 --> 0:20:04.000 And then they're looking for heat and humidity. And so 0:20:04.240 --> 0:20:06.280 I don't think we know exactly how they decide, like 0:20:06.359 --> 0:20:08.640 I'm going to bite their arm as opposed to their leg. 0:20:08.680 --> 0:20:10.840 It might be whatever they encounter first, because you want 0:20:10.840 --> 0:20:13.000 to get the bite in there and get out. But yeah, 0:20:13.040 --> 0:20:15.119 those are the cues that they use. The cues change 0:20:15.160 --> 0:20:17.800 depending on how close they are to us. Some people 0:20:17.840 --> 0:20:20.720 give off more cues, as Katrina mentioned, that could be 0:20:20.720 --> 0:20:23.720 because of their microbiome. There's some evidence that women in 0:20:23.760 --> 0:20:27.119 their third trimester are also more attractive to mosquitoes. And 0:20:27.160 --> 0:20:30.159 the idea there is that we are breathing more and 0:20:30.240 --> 0:20:32.399 more heavily and we give off more CO two, so 0:20:32.440 --> 0:20:35.760 we're easier for mosquitos to find. I certainly was breathing heavily. 0:20:35.760 --> 0:20:38.119 I remember my mom being like, do you have to 0:20:38.160 --> 0:20:38.879 be so loud? 0:20:39.359 --> 0:20:42.959 And I was like I do. I'm breathing for two. 0:20:43.960 --> 0:20:44.080 Uh. 0:20:45.280 --> 0:20:49.080 But yeah, the mosquitoes apparently love that. All right, So 0:20:49.280 --> 0:20:52.120 now we know how mosquitoes find us, But now how 0:20:52.119 --> 0:20:54.840 do you figure out how many mosquitoes are in an area? 0:20:55.560 --> 0:20:59.080 So Robert had this great insight, which is that often 0:20:59.119 --> 0:21:00.960 when we are trying to faitigure out how many of 0:21:01.000 --> 0:21:04.119 a certain species is in a particular environment, we use 0:21:04.160 --> 0:21:07.639 this technique called mark recapture, and it would be really 0:21:07.640 --> 0:21:11.320 hard to mark and recapture mosquito. So mark recapture is 0:21:11.320 --> 0:21:13.840 a procedure where you essentially go out into an environment 0:21:14.080 --> 0:21:17.040 twice to collect animals. The first time you go out, 0:21:17.320 --> 0:21:19.440 you collect you know, as many animals as you can 0:21:19.520 --> 0:21:22.000 with whatever technique. So, for example, I used to go 0:21:22.040 --> 0:21:24.520 sample fish and I would use what's called fight nets. 0:21:24.840 --> 0:21:27.840 You essentially put a net that goes one side of 0:21:27.840 --> 0:21:29.520 it is in like the middle of a lake. The 0:21:29.560 --> 0:21:32.240 other side goes to the shoreline. As the fish swim 0:21:32.280 --> 0:21:34.480 along the shoreline, they hit the net that hits the 0:21:34.480 --> 0:21:37.159 shoreline and they follow it essentially into a funnel that 0:21:37.200 --> 0:21:39.359 they can't get out of. And then you sample that 0:21:39.400 --> 0:21:42.480 once a day. Does that make sense mm hm? Okay, 0:21:42.520 --> 0:21:45.360 So we trap fish, we take the fish out, we 0:21:45.680 --> 0:21:48.119 tag the fish in a way where we will know 0:21:48.200 --> 0:21:50.639 if we've seen them before or not, and then we 0:21:50.680 --> 0:21:53.400 release them back into the environment. And then a week 0:21:53.480 --> 0:21:55.280 or two later, we go out again and we use 0:21:55.359 --> 0:21:57.920 another technique to catch as many fish as we can. 0:21:58.000 --> 0:22:00.840 In this case, we're using an electro fishing boat where 0:22:00.880 --> 0:22:03.520 you stun the fish temporarily, you bring them into a 0:22:03.560 --> 0:22:06.200 live well on the boat where it's got a lot 0:22:06.200 --> 0:22:08.840 of water circulating so that they can come to and 0:22:08.840 --> 0:22:12.040 stay safe. And then you count how many fish you collected, 0:22:12.080 --> 0:22:14.680 and you look to see how many of them you're 0:22:14.760 --> 0:22:16.920 catching for the second time, so how many of them 0:22:16.920 --> 0:22:19.640 showed up in both of your samples, And so then 0:22:19.680 --> 0:22:23.919 you're making this assumption that the proportion of animals that 0:22:23.960 --> 0:22:28.119 you re caught in your second sample is similar to 0:22:28.160 --> 0:22:31.919 the proportion of animals that you caught the first time 0:22:32.520 --> 0:22:36.000 in the entire population. So, for example, if I caught 0:22:36.040 --> 0:22:38.400 fifty fish in my first sample and marked them all, 0:22:38.720 --> 0:22:40.520 and then I went out and I caught one hundred 0:22:40.600 --> 0:22:43.719 fish in my second sample, ten of which were already 0:22:43.720 --> 0:22:46.600 marked individuals, the way that I would capture this is 0:22:46.640 --> 0:22:49.280 I would say fifty times one hundred which is the 0:22:49.359 --> 0:22:52.159 number of fish I captured in both of my samples, 0:22:52.520 --> 0:22:54.960 and divide by ten, which is the number of individuals 0:22:55.000 --> 0:22:57.359 I caught twice, and that would give me an estimate 0:22:57.359 --> 0:23:00.439 that there's five hundred fish in the population, all right. 0:23:00.280 --> 0:23:02.600 So the goal here is to get a sense for 0:23:02.680 --> 0:23:04.920 how many animals there are total. Of course, you can't 0:23:04.960 --> 0:23:08.280 measure all of the animals, and so you measure twice 0:23:08.400 --> 0:23:10.520 and then you look at the overlap because like, if 0:23:10.560 --> 0:23:12.920 you have one hundred percent overlap between your two measurements, 0:23:13.200 --> 0:23:15.040 that means you have a smaller population. If you have 0:23:15.119 --> 0:23:17.520 no overlap between your two measurements, then you have a 0:23:17.520 --> 0:23:20.679 bigger population because you're getting like different subsets of the 0:23:20.680 --> 0:23:22.560 whole population. Is that the way to think. 0:23:22.480 --> 0:23:23.320 About it exactly? 0:23:23.480 --> 0:23:25.879 Yes, Yeah, Like if you mark one hundred fish and 0:23:25.920 --> 0:23:28.320 then the next day every single fish is marked, it 0:23:28.400 --> 0:23:30.960 suggests there's not really any other fish out there. But 0:23:31.040 --> 0:23:33.240 if only ten percent of them are marked, then it 0:23:33.320 --> 0:23:36.320 suggests that the population has another ninety percent out. 0:23:36.240 --> 0:23:39.600 There, right, cool, all right, So that's how mark and 0:23:39.640 --> 0:23:41.960 recapture studies work to get a sense for like how 0:23:41.960 --> 0:23:44.560 many birds are there, or how many cheetahs are there, 0:23:44.880 --> 0:23:47.520 But what do you do for mosquitoes. You can't capture 0:23:47.720 --> 0:23:49.119 and mark mosquitoes, can you. 0:23:49.600 --> 0:23:51.680 So first of all, thanks team, it was very helpful 0:23:51.720 --> 0:23:54.280 to have your input on that. Yeah, so marking and 0:23:54.320 --> 0:23:57.439 recapturing mosquitoes would be kind of nuts because they're so 0:23:57.560 --> 0:23:59.680 small and so delicate that when you go to catch 0:23:59.720 --> 0:24:03.119 them and count them, unfortunate, well maybe not unfortunately, you 0:24:03.240 --> 0:24:05.240 usually kill them in the process of counting them. And 0:24:05.280 --> 0:24:07.639 so how could you mark a mosquito and release it? 0:24:07.680 --> 0:24:11.320 And the answer is they usually don't. So when a 0:24:11.320 --> 0:24:13.679 lot of companies are trying, for example, to see how 0:24:13.680 --> 0:24:16.000 many mosquitos are out there, what they'll do essentially is 0:24:16.119 --> 0:24:18.919 grow males in the lab and they'll throw out all 0:24:18.920 --> 0:24:20.440 of the females because you don't want to put any 0:24:20.440 --> 0:24:22.879 extra mosquitos out there that will be biting anybody and 0:24:22.880 --> 0:24:25.760 taking blood meals. But since the males don't take blood meals, 0:24:26.080 --> 0:24:28.560 they hatch them out of eggs in the lab, and 0:24:28.600 --> 0:24:31.320 then when they go to emerge to go from the 0:24:31.320 --> 0:24:34.600 water to their like air phase, they put a powder 0:24:34.720 --> 0:24:38.119 on the surface of the water and it's a fluorescent powder, 0:24:38.200 --> 0:24:41.520 so as the mosquitoes emerge through it they get covered 0:24:41.560 --> 0:24:42.720 in this fluorescent dust. 0:24:43.040 --> 0:24:45.119 Wow, and you get fabulous mosquitos. 0:24:45.280 --> 0:24:46.960 And you get fabulous mosquitos. 0:24:47.000 --> 0:24:49.840 You can also genetically modify them so that they fluoresc 0:24:49.960 --> 0:24:53.159 green based on a protein that they're making themselves. But 0:24:53.240 --> 0:24:55.240 one way or another, you're making it so that the 0:24:55.560 --> 0:24:58.840 animals that you've released into the wild are detectable in 0:24:58.920 --> 0:25:01.560 some way that it didn't require you to like handle them, 0:25:01.600 --> 0:25:05.600 which could kill them. So now instead of doing mark 0:25:06.160 --> 0:25:09.120 and recapture, you mark in the lab and then when 0:25:09.119 --> 0:25:11.640 you go out you can put, for example, a giant 0:25:11.720 --> 0:25:15.720 tub with dry ice which releases CO two that attracts 0:25:15.720 --> 0:25:18.520 the mosquitoes, and so you find a way to capture them. 0:25:18.840 --> 0:25:21.119 And then you look at the proportion of mosquitos that 0:25:21.160 --> 0:25:23.720 you recapture that fluores when you look at them, and 0:25:23.720 --> 0:25:25.560 you'll say, okay, those are the ones we added to 0:25:25.600 --> 0:25:28.840 the environment from the lab. And then you compare that 0:25:29.000 --> 0:25:31.479 to the number that didn't fluoresse, which were the wild 0:25:31.520 --> 0:25:34.040 animals that you're catching for the first time. And this 0:25:34.119 --> 0:25:36.600 process does kill them while you're doing the counting. Does 0:25:36.640 --> 0:25:37.200 that make sense? 0:25:37.600 --> 0:25:39.919 Yes, So if you attract and capture a bunch of 0:25:39.920 --> 0:25:42.879 mosquitos and they're all your fluorescent ones. It suggests that 0:25:42.920 --> 0:25:46.040 your fluorescent ones are dominating the population. And if they 0:25:46.080 --> 0:25:48.439 come back and you see almost none of your fluorescent ones, 0:25:48.480 --> 0:25:50.840 it means that there are a tiny fraction of the population. 0:25:50.960 --> 0:25:53.720 So there's a bunch out there. Exactly what I wonder is, like, 0:25:54.040 --> 0:25:56.760 how many other crazy ideas did they come up with 0:25:56.840 --> 0:26:00.520 before this crazy idea that they made work. I love 0:26:00.600 --> 0:26:04.400 the experimental creativity of science this way, you know. 0:26:04.359 --> 0:26:07.600 Like this is a hilarious idea, But I would really 0:26:07.640 --> 0:26:10.040 love to see the whiteboard where they came up with 0:26:10.080 --> 0:26:13.280 all sorts of bizarre ideas, including like you know, laser 0:26:13.320 --> 0:26:14.680 pointers or who knows what. 0:26:15.960 --> 0:26:19.199 There are some more complicated methods, so for example, you 0:26:19.240 --> 0:26:22.800 can like look at how many batches of eggs appear 0:26:22.840 --> 0:26:24.960 to have been laid in like some water that you 0:26:25.000 --> 0:26:27.040 put out, and then you can try to extrapolate from 0:26:27.040 --> 0:26:29.560 the batches of eggs how many females likely came by 0:26:29.640 --> 0:26:33.600 to lay those eggs. And it's much more complicated and 0:26:33.840 --> 0:26:36.000 there's a lot more guesswork because you have to like 0:26:36.320 --> 0:26:38.400 have an estimate for the average number of eggs laid 0:26:38.440 --> 0:26:40.800 by a female, for example. But yes, I think it 0:26:40.920 --> 0:26:44.800 is a beautiful technique to release fluorescent mosquitoes who can't 0:26:44.800 --> 0:26:46.639 bite you and then see how many of them you 0:26:46.680 --> 0:26:47.080 get back. 0:26:47.359 --> 0:26:50.200 And this is important because it's like a basic element 0:26:50.400 --> 0:26:53.320 of mosquito science. It just like to know what are 0:26:53.320 --> 0:26:56.359 the populations and where are they, right, because without basic 0:26:56.480 --> 0:26:59.199 knowledge you can't do anything. But I think a lot 0:26:59.200 --> 0:27:01.640 of people underest to me, like how much work goes 0:27:01.680 --> 0:27:05.119 into just getting some basic information. Like we had our 0:27:05.119 --> 0:27:08.159 episode about weather, and like just knowing what is the 0:27:08.160 --> 0:27:11.720 temperature everywhere on the Earth would be hugely helpful, and 0:27:11.800 --> 0:27:13.800 we can't know that. We don't know that, and so 0:27:14.080 --> 0:27:18.160 just like knowing where the mosquitoes are would be massively beneficial, 0:27:18.160 --> 0:27:18.760 I imagine. 0:27:18.880 --> 0:27:19.080 Yeah. 0:27:19.080 --> 0:27:21.000 And actually, I don't know if you guys have ever 0:27:21.160 --> 0:27:23.760 talked about the citizen science projects that are the reason 0:27:23.840 --> 0:27:28.520 we have information about insect population size. But for example, 0:27:28.800 --> 0:27:30.800 many of us have noticed that our windshields are not 0:27:30.840 --> 0:27:32.440 covered in bugs when we go on a read trip 0:27:32.480 --> 0:27:35.760 these days, and that's because the insect populations have declined 0:27:35.800 --> 0:27:38.399 so much. And there are citizen science projects where people 0:27:38.400 --> 0:27:39.919 will like put nets kind of like the one you 0:27:39.960 --> 0:27:42.639 described on the top of their cars and drive around 0:27:42.760 --> 0:27:45.000 and just catch all the insects and count them. And 0:27:45.040 --> 0:27:47.680 there were people that were doing that in Germany throughout 0:27:47.680 --> 0:27:49.800 the twentieth century, and that is a big part of 0:27:49.880 --> 0:27:51.959 why we know about the insect decline. Like if they 0:27:52.000 --> 0:27:54.040 hadn't done that, we just wouldn't even know. 0:27:54.440 --> 0:27:55.679 Wow, I didn't know about that. 0:27:56.040 --> 0:28:00.520 Yeah, that's amazing. Thank you. Weird German insects capture people. 0:28:01.880 --> 0:28:04.240 There are people out there who have enthusiasm for everything. 0:28:04.320 --> 0:28:07.040 It's incredible. Yes, well, I need a break from all 0:28:07.040 --> 0:28:09.760 of these mosquitoes. I gotta go scratch some itches and 0:28:09.800 --> 0:28:12.240 when we come back, we're going to talk more about 0:28:12.240 --> 0:28:14.840 how mosquitoes do what they do and how we do 0:28:14.920 --> 0:28:19.160 what we do best, which is kill mosquitoes. Wow. 0:28:19.240 --> 0:28:21.639 Thank you for those answers, Daniel and Kelly. What are 0:28:21.640 --> 0:28:25.280 relief knowing that mosquitoes aren't able to coordinate their attacks? 0:28:25.400 --> 0:28:28.600 Let's hope they do not evolve that ability anytime soon. 0:28:29.520 --> 0:28:33.639 Also so amazed that biologists have figured out a way 0:28:33.720 --> 0:28:37.960 to estimate mosquito populations. Sorry, Kelly, I will never doubt 0:28:38.120 --> 0:28:41.720 biologists again. Let's get whoever came up with that idea 0:28:41.800 --> 0:28:45.440 working on quantum gravity soon. Love the show. Thank you, 0:28:45.480 --> 0:29:04.920 guys so much. Shout out to my Spring Street students. 0:29:07.960 --> 0:29:10.280 Okay, we're back and I'm very excited for this segment 0:29:10.280 --> 0:29:13.040 of the podcast where we get to take scientific revenge 0:29:13.160 --> 0:29:15.240 on all the mosquitoes that have caused me to suffer 0:29:15.360 --> 0:29:15.920 so much. 0:29:16.280 --> 0:29:19.760 All right, so we have this question from a listener, James, 0:29:19.760 --> 0:29:21.960 and let's go ahead and listen to James's question. 0:29:22.280 --> 0:29:24.600 Hi, Daniel and Kelly, I was wondering if you could 0:29:24.640 --> 0:29:27.479 cover gene drives. It seems like this technology has been 0:29:27.520 --> 0:29:30.440 out for a long time but hasn't been deployed. It 0:29:30.480 --> 0:29:33.800 seems like a magical technology for wiping out invasive species. 0:29:34.280 --> 0:29:36.840 When you have invasive mosquitoes wiping out the last native 0:29:36.840 --> 0:29:39.880 Hawaiian songbirds with av and malaria, you have to ask 0:29:39.920 --> 0:29:42.600 why you wouldn't test this out on such isolated islands. 0:29:42.920 --> 0:29:45.760 What terrifying scenarios are keeping them from deploying gene drives 0:29:45.760 --> 0:29:48.960 in the outside world. Are those scenarios realistic or is 0:29:49.000 --> 0:29:52.000 the pesticide industry just bumping off gene drive researchers. 0:29:52.480 --> 0:29:55.560 Thanks, all right, So we have tried lots of things 0:29:55.600 --> 0:29:58.280 to kill mosquitoes with varying success. 0:29:58.720 --> 0:29:59.840 One of the things we tried. 0:30:00.000 --> 0:30:03.920 Initially was spraying a bunch of insecticides, and that worked 0:30:03.920 --> 0:30:06.600 for a while, but eventually the mosquitoes that happened to 0:30:06.600 --> 0:30:10.600 be resistant to the insecticides had a lot more babies. 0:30:10.640 --> 0:30:14.320 And now we have populations of insecticide resistant mosquitos. 0:30:14.600 --> 0:30:16.800 How does that even possibly work? I mean, I see 0:30:16.840 --> 0:30:20.320 like trucks driving around spraying insecticide, but I'm like, you know, 0:30:20.360 --> 0:30:23.080 what fraction of the mosquitoes are they going to be 0:30:23.160 --> 0:30:26.640 hitting with that? It seems like, you know, shooting individual 0:30:26.800 --> 0:30:28.560 pigeons in the park or something. 0:30:28.640 --> 0:30:32.480 It's like hopeless, right, Yeah, And sometimes they release it airborne. 0:30:32.480 --> 0:30:36.040 Other times they'll specifically release insecticides into like waterways where 0:30:36.080 --> 0:30:38.760 mosquitoes are breeding, and that's a little bit more targeted. 0:30:39.560 --> 0:30:41.760 Either way, you're probably killing a bunch of stuff you 0:30:41.800 --> 0:30:44.320 don't intend on killing as well, because a lot of 0:30:44.320 --> 0:30:46.719 these things are not specific just for mosquitoes. 0:30:47.040 --> 0:30:49.480 And then aren't people going to end up drinking insecticide? 0:30:49.560 --> 0:30:50.560 Yeah, or breathing it in? 0:30:50.640 --> 0:30:55.400 I remember whenever the insecticide trucks would come through in California, 0:30:56.160 --> 0:30:58.000 I would run inside the house or I'd bring my 0:30:58.040 --> 0:31:01.120 baby inside of the house. And yeah, so you breathe 0:31:01.160 --> 0:31:03.120 it in presumably. I mean they try to make it 0:31:03.160 --> 0:31:07.440 so that these chemicals are specifically focusing in on things 0:31:07.800 --> 0:31:10.880 mosquitoes and other insects do and not things that happen 0:31:10.920 --> 0:31:13.520 inside the human body. I don't know how well we're 0:31:13.520 --> 0:31:15.440 often able to do that, Katrina, do you have any 0:31:15.440 --> 0:31:16.120 insights there? 0:31:16.280 --> 0:31:19.360 Yeah, oh, exactly, that's the idea, But I think that's 0:31:19.560 --> 0:31:22.720 extremely hard. I mean, when it comes to viruses and microbes, 0:31:22.760 --> 0:31:24.800 it's easier to come up with targets that are totally 0:31:24.920 --> 0:31:27.800 orthogonal to what would happen to a person, But that's 0:31:27.840 --> 0:31:29.160 so much harder for insects. 0:31:29.160 --> 0:31:31.320 Like we're a little more closely related, believe it or not. 0:31:31.520 --> 0:31:33.000 To insects than we are to microbes. 0:31:33.120 --> 0:31:35.520 Yeah, yeah, exactly, so it's harder to come up with 0:31:35.680 --> 0:31:36.680 distinct targets. 0:31:36.680 --> 0:31:38.680 But yeah, that's definitely the goal. 0:31:38.760 --> 0:31:42.560 But I think there's all kinds of off target impacts. 0:31:42.600 --> 0:31:44.920 Like I'm sure you guys remember hearing about the Peregon 0:31:45.000 --> 0:31:48.480 falcons and the compromised egg structure that came from all 0:31:48.480 --> 0:31:50.800 the insecticides being sprayed in the sixties. 0:31:51.200 --> 0:31:54.280 Yeah, right, the DDT. Yeah, I think Rachel Carson wrote 0:31:54.360 --> 0:31:57.680 about that in silent spring. Yes, So we use these insecticides, 0:31:57.680 --> 0:31:59.480 and we're trying to use them in a little bit 0:31:59.480 --> 0:32:02.080 more specific ways. So, for example, you can dip a 0:32:02.120 --> 0:32:04.440 bed net in insecticides, and then you can put the 0:32:04.480 --> 0:32:06.800 bed net over your bed and then at the time 0:32:06.800 --> 0:32:09.480 of day when mosquitos are most likely to bite, you're 0:32:09.520 --> 0:32:12.360 protected inside of the bed net, and because it has 0:32:12.400 --> 0:32:14.520 already soaked into the bed net, you're not breathing a 0:32:14.560 --> 0:32:17.040 lot in or you're not drinking it in water. But 0:32:17.160 --> 0:32:20.520 the problem is that there's very strong selection pressure for 0:32:20.640 --> 0:32:23.440 mosquitoes to find routes around this. So, for example, if 0:32:23.480 --> 0:32:27.000 you've got mosquitos that bite at night, if there's variability 0:32:27.000 --> 0:32:29.240 and some mosquitoes are biting a little bit earlier in 0:32:29.280 --> 0:32:32.200 the day, the ones that bite earlier in the day 0:32:32.560 --> 0:32:34.920 are going to catch the early birds and then they're 0:32:34.960 --> 0:32:36.800 going to have a lot more babies that go early 0:32:36.840 --> 0:32:39.520 in the day. And now the bed net isn't as helpful. 0:32:39.520 --> 0:32:41.520 And we've actually been finding that in some parts of 0:32:41.520 --> 0:32:44.479 the world mosquitos are changing there the time of day 0:32:44.480 --> 0:32:46.920 when they're most active, so that they are now going 0:32:47.000 --> 0:32:49.160 after people when they're outside of the bed nets. 0:32:49.360 --> 0:32:52.000 Wow, And this is why when I came back from 0:32:52.040 --> 0:32:54.560 a trip to Tahiti where we had to sleep with 0:32:54.640 --> 0:32:57.520 bed nets every night, and I loved waking up without 0:32:57.520 --> 0:32:59.640 any bites. I just set up the bed net on 0:32:59.680 --> 0:33:02.040 our couch and then for weeks, I just like, anytime 0:33:02.040 --> 0:33:04.280 I'm hanging on the couch, I'm under the mosquito net. 0:33:04.280 --> 0:33:07.200 No big deal. I'm like impervious. I'm like laughing at 0:33:07.200 --> 0:33:08.000 all the mosquitoes. 0:33:08.080 --> 0:33:08.480 Ha ha. 0:33:09.960 --> 0:33:13.440 It was a very interesting sight, Daniel, Like watching TV 0:33:13.840 --> 0:33:15.560 while sitting inside the bed net. 0:33:15.880 --> 0:33:19.160 It's amazing, amazing because I don't feel any social pressure 0:33:19.200 --> 0:33:21.560 to be bitten by mosquitos, so I don't look like 0:33:21.760 --> 0:33:25.120 a weird under a bench. I was happy. It was great, 0:33:25.960 --> 0:33:28.440 and now I know that ecologically I was, you know, 0:33:28.560 --> 0:33:30.960 suppressing mosquitos in a balanced way. So yeah, I was 0:33:31.000 --> 0:33:31.760 being responsible. 0:33:31.840 --> 0:33:33.760 Way to go, Daniel, Thank you, pat on the back. 0:33:33.680 --> 0:33:35.200 All right, that's what I wanted. Thank you very much. 0:33:35.680 --> 0:33:39.280 So mosquitos essentially are constantly providing a moving target where 0:33:39.320 --> 0:33:43.200 there's selection for them to route around whatever methods that 0:33:43.240 --> 0:33:45.160 we are using to try to keep them at bay. 0:33:46.120 --> 0:33:49.440 People also use things like they'll dump mosquitofish into waterways. 0:33:49.440 --> 0:33:51.960 These are tiny little fish that eat the aquatic stages 0:33:51.960 --> 0:33:53.120 of the mosquito. 0:33:52.920 --> 0:33:53.880 My new favorite fish. 0:33:54.000 --> 0:33:56.080 Yeah, But then the problem is they also out compete 0:33:56.080 --> 0:33:58.240 a bunch of native fish, and they cause problems in 0:33:58.240 --> 0:34:01.080 the ecosystems that you introduce them in because they're not 0:34:01.160 --> 0:34:03.880 native there. So it's not a perfect method, but it's 0:34:03.880 --> 0:34:06.200 a method you can use in some areas at your 0:34:06.200 --> 0:34:08.440 own house. Now that you know that there's an aquatic stage. 0:34:08.440 --> 0:34:10.120 Maybe you already knew that, but you can make sure 0:34:10.120 --> 0:34:12.880 that you dump any standing water and if you want to, 0:34:13.000 --> 0:34:15.520 like have a bird bath, just dump it out every 0:34:15.600 --> 0:34:17.399 day or two and then refill it because that won't 0:34:17.400 --> 0:34:20.600 give the mosquitos time to hatch. But trying to like 0:34:20.760 --> 0:34:22.960 up the complication level a little bit. The next thing 0:34:23.040 --> 0:34:26.400 that we started in the nineteen fifties was using sterile 0:34:26.480 --> 0:34:29.479 insect technique, and folks might remember that we talked about 0:34:29.480 --> 0:34:32.719 this a bit for the screwworm episode, and the idea here, 0:34:32.880 --> 0:34:37.279 essentially is that you blast mosquitoes with gamma rays or 0:34:37.320 --> 0:34:41.440 other chemicals that sterilize them, and then you release just 0:34:41.560 --> 0:34:45.440 the males into the environment. Female mosquitos mate once and 0:34:45.480 --> 0:34:47.719 they'll mate with one of these sterile males, and then 0:34:47.840 --> 0:34:50.960 if they're able to lay eggs, those eggs won't hatch, 0:34:51.280 --> 0:34:54.640 And so essentially you are taking females out of the 0:34:54.640 --> 0:34:58.200 population reproductively by having them mate with males where it 0:34:58.239 --> 0:35:01.320 won't result in successful offspring. But this method has a 0:35:01.360 --> 0:35:04.719 couple problems. First of all, if you are just like 0:35:04.960 --> 0:35:09.359 randomly bombarding insects with gamma rays, yes you're gonna sterilize them, 0:35:09.360 --> 0:35:11.200 but you also might beat them up in a bunch 0:35:11.200 --> 0:35:14.400 of other ways. And so sometimes these males that you 0:35:14.440 --> 0:35:17.120 release into the environment aren't as good at attracting the 0:35:17.200 --> 0:35:20.319 ladies as the wild males, because these males have all 0:35:20.320 --> 0:35:22.160 sorts of other things wrong with them. 0:35:22.160 --> 0:35:24.680 Since Kelly, I read a bunch of comic books, and 0:35:24.760 --> 0:35:28.920 if you blasphamilar with gamma rays, it usually gives it superpowers. Right, Yeah, 0:35:28.960 --> 0:35:31.320 are you telling me that particle physics isn't really connecting 0:35:31.320 --> 0:35:32.880 with the biology there? Is that what's happening? 0:35:33.000 --> 0:35:35.360 I think that's what's happening, Daniel. I'm really sorry. Or 0:35:35.360 --> 0:35:38.040 maybe it's a statistical thing. Sometimes it works out that way. 0:35:38.080 --> 0:35:40.640 But the mosquitos just they there hasn't been the Spider 0:35:40.680 --> 0:35:42.319 Man equivalent for mosquitoes yet. 0:35:43.200 --> 0:35:44.960 Yeah, I'm glad that we haven't turned any of these 0:35:45.040 --> 0:35:48.000 mosquitoes into the incredible hulk mosquito. Yeah, that would be 0:35:48.080 --> 0:35:49.120 really excite to see that. 0:35:49.320 --> 0:35:50.040 It would be mad. 0:35:50.360 --> 0:35:52.839 Yeah, I bet the fabulous mosquitos do great though. 0:35:53.680 --> 0:35:57.640 Yeah. 0:35:57.680 --> 0:36:00.440 And actually I have a colleague at the City of 0:36:00.440 --> 0:36:03.880 Hawaii who's working on the microbiome. It's actually in the 0:36:03.920 --> 0:36:06.799 context of gene drives, but they are working on making 0:36:06.880 --> 0:36:11.160 the microbiome of the mosquitos robust to help the mosquitos 0:36:11.160 --> 0:36:13.840 that they're engineering to go out there and succeed with 0:36:13.880 --> 0:36:14.719 the ladies. 0:36:14.440 --> 0:36:14.919 As it were. 0:36:15.600 --> 0:36:18.120 Nice. Is this Wallbakia, No, it's mosquitos. 0:36:18.120 --> 0:36:19.160 It's a malaria project. 0:36:19.200 --> 0:36:22.320 It's Nicole Hinson at the University of Hawaii by Walbakia. 0:36:22.360 --> 0:36:24.879 I meant the bacteria that they're adding. But anyway, we'll 0:36:24.880 --> 0:36:25.800 get back to Wallbachia. 0:36:26.000 --> 0:36:28.880 So no, I think that they are like more roundly 0:36:29.239 --> 0:36:31.839 making the microbiome of the mosquito robust, so that in 0:36:31.920 --> 0:36:33.480 general the mosquito is robust. 0:36:33.480 --> 0:36:36.799 I'm not sure, but again with this method, I wonder, like, 0:36:36.840 --> 0:36:38.640 how many males do you have to put out there 0:36:38.800 --> 0:36:40.799 to have this have any efficacy. It's not like the 0:36:40.800 --> 0:36:43.600 males are reproducing and making more of themselves, right, so 0:36:43.640 --> 0:36:45.840 like every one you put out, it's one that you 0:36:46.040 --> 0:36:49.120 essentially manufactured. Is it really possible to have an impact 0:36:49.120 --> 0:36:49.760 on the population. 0:36:50.000 --> 0:36:53.400 Yeah, great question. So there was an experiment done in Havana, Cuba. 0:36:53.719 --> 0:36:55.600 Sorry I said that wrong, but that's what we expect 0:36:55.600 --> 0:36:59.600 out of me. Where about one and a quarter million 0:36:59.840 --> 0:37:02.640 or radiated mosquitos in this case, the species was eighties 0:37:02.800 --> 0:37:07.000 jipdi were released and again all males, and they did 0:37:07.000 --> 0:37:09.680 a twenty week trial and they looked at a fifty 0:37:09.719 --> 0:37:12.040 hectare area, so a pretty big area, and they put 0:37:12.080 --> 0:37:14.919 out what they called ovtraps, essentially just like areas where 0:37:14.920 --> 0:37:18.600 mosquitoes could lay eggs, and they didn't find any eggs 0:37:18.640 --> 0:37:21.880 in that fifty hectar area, suggesting that one in a 0:37:21.920 --> 0:37:24.640 quarter million mosquitoes, which is a lot of mosquitoes, is 0:37:24.800 --> 0:37:27.680 enough to essentially knock a population down in an area. 0:37:27.719 --> 0:37:30.120 But the problem is you got to keep doing that 0:37:30.360 --> 0:37:32.560 over and over and over again every year. So it's 0:37:32.560 --> 0:37:35.799 an expensive process that needs to be maintained. But it 0:37:35.800 --> 0:37:38.960 turns out it doesn't work well for anophlies mosquitos. So 0:37:39.000 --> 0:37:42.600 we talked about eighties mosquitoes. There's another genus of mosquitos 0:37:42.640 --> 0:37:44.759 called Anophlies that also tends to have a lot of 0:37:44.800 --> 0:37:48.640 species that transmit diseases to us, and that species it 0:37:48.680 --> 0:37:50.840 looks like it's a little bit harder at the early 0:37:50.880 --> 0:37:52.880 stages of their life to figure out which ones are 0:37:52.920 --> 0:37:55.880 males and which ones are females. And if you can't 0:37:55.880 --> 0:37:58.320 be sure, then maybe you're releasing a bunch of extra 0:37:58.360 --> 0:38:00.879 females into the environment who are like go and start 0:38:00.880 --> 0:38:05.400 biting people and possibly transmit diseases. So it works okay 0:38:05.400 --> 0:38:07.719 for eighties a jipdi if you're willing to release it 0:38:07.760 --> 0:38:09.960 over and over again over a large area, But it 0:38:10.000 --> 0:38:11.920 works less well for an off lease because there's this 0:38:12.000 --> 0:38:13.719 step where you need to figure out if there are 0:38:13.800 --> 0:38:16.759 boy mosquitos or girl mosquitos, and because that's hard to 0:38:16.760 --> 0:38:18.759 do in the lab, that makes this technique a little 0:38:18.760 --> 0:38:22.960 harder to use. So next, let's talk about bacteria. So 0:38:23.200 --> 0:38:28.120 I suspect to have Katrina's attention. So Wolbakia is a 0:38:28.120 --> 0:38:31.120 gram negative bacteria that's carried by a bunch of different 0:38:31.200 --> 0:38:36.200 kinds of insects. It lives inside of insects cells and 0:38:36.280 --> 0:38:40.560 it only passes down the female line, and so it's 0:38:40.640 --> 0:38:44.040 found ways to manipulate a lot of different insects species 0:38:44.080 --> 0:38:47.440 to help it transmit from one generation to another. So 0:38:47.719 --> 0:38:50.719 if a male who has the bacteria mates with the 0:38:50.760 --> 0:38:54.760 female who doesn't, the eggs that she produces won't hatch. 0:38:55.640 --> 0:38:58.600 But if the female has Wolbachia and the male doesn't, 0:38:58.719 --> 0:39:02.239 then she will lay as that all carry Woolbachia. And 0:39:02.280 --> 0:39:04.680 so essentially the bacteria has a way of sort of 0:39:05.000 --> 0:39:08.799 manipulating things so that eggs are produced in ways where 0:39:08.840 --> 0:39:12.279 the bacteria can transmit and in instances where the bacteria 0:39:12.440 --> 0:39:14.360 wouldn't be able to transmit. It just sort of like 0:39:14.400 --> 0:39:17.680 stops reproduction dead, so that there's a line there where 0:39:17.719 --> 0:39:20.719 nothing's happening. So in this way it can permeate the 0:39:20.840 --> 0:39:21.560 entire population. 0:39:21.800 --> 0:39:24.879 That's mind boggling. The sort of like genetic engineering by 0:39:24.920 --> 0:39:28.480 the bacteria to ensure that only lines that have the 0:39:28.480 --> 0:39:30.239 bacteria continue, that's incredible. 0:39:30.480 --> 0:39:33.359 It is incredible. Yeah, I remember when I first learned 0:39:33.400 --> 0:39:35.440 about this. It's kind of like blood types or something 0:39:35.480 --> 0:39:39.040 that there's like this incompatibility. But I know it's given 0:39:39.080 --> 0:39:42.640 people a real handle for engineering the populations. So I 0:39:42.719 --> 0:39:44.920 can only imagine what you're going to say next. 0:39:45.600 --> 0:39:47.600 So what I'm going to say next is that Scott 0:39:47.600 --> 0:39:52.040 O'Neill at Monash University noted that a different lab had 0:39:52.080 --> 0:39:56.520 found that viruses and fruit flies have trouble growing when 0:39:56.520 --> 0:39:58.040 they're infected by wolbachia. 0:39:58.560 --> 0:40:00.360 So this has nothing to do with REP production. 0:40:00.440 --> 0:40:03.000 This is just if wolbachia is there, it prevents the 0:40:03.040 --> 0:40:05.760 growth of viruses that otherwise would have killed the fruit flies. 0:40:06.480 --> 0:40:09.040 So O'Neil was like, well, what if we take wolbachia 0:40:09.080 --> 0:40:12.840 out of fruit flies and put it in mosquito eggs 0:40:13.320 --> 0:40:17.640 and then see if mosquitoes carrying this wolbachia are less 0:40:17.719 --> 0:40:21.520 likely to transmit dengae, which is another yeah, mosquito transmitted 0:40:21.560 --> 0:40:24.160 disease that can be lethal. And so essentially they did 0:40:24.200 --> 0:40:29.400 the incredibly difficult job of extracting a teeny tiny bacteria 0:40:29.440 --> 0:40:32.280 from a fruit fly sticking it into a teeny tiny 0:40:32.320 --> 0:40:34.360 little mosquito egg. Apparently they had to do this like 0:40:34.440 --> 0:40:37.759 thousands of times before it worked, but they eventually were 0:40:37.800 --> 0:40:41.120 able to get a strain of mosquitoes that were infected 0:40:41.160 --> 0:40:43.480 by the wolbachia that was found in these fruit flies. 0:40:43.800 --> 0:40:47.120 So you're telling me that they found a strain of 0:40:47.160 --> 0:40:51.000 Wolbachia that kills viruses, and since dangay is a virus, 0:40:51.040 --> 0:40:53.920 they were like, maybe this strain of Wolbachia is going 0:40:53.960 --> 0:40:56.440 to also kill dngay. That's crazy. 0:40:56.800 --> 0:40:59.640 It doesn't necessarily kill the virus. 0:40:59.239 --> 0:41:01.200 But it makes it so the virus can't reproduce, and 0:41:01.239 --> 0:41:03.560 if the virus can't reproduce, it can't go from mosquito 0:41:03.600 --> 0:41:06.560 to mosquito. And so they did some lab experiments and 0:41:06.600 --> 0:41:09.600 it was working well in the lab. And in fact, 0:41:09.840 --> 0:41:12.880 one of our listeners, Joe, sent us an email that 0:41:12.960 --> 0:41:16.400 included a link to an article where Wobakia infected mosquitoes 0:41:16.440 --> 0:41:19.880 had been released in Florida. So we're trying this like 0:41:19.960 --> 0:41:20.760 out in the wild. 0:41:21.120 --> 0:41:21.359 Wow. 0:41:21.640 --> 0:41:23.680 And so the question is does it work? And I 0:41:23.760 --> 0:41:26.359 looked for a really long time to try to find 0:41:26.400 --> 0:41:29.399 studies that had quantified this working, and I was able 0:41:29.400 --> 0:41:32.640 to find one study and it was in Indonesia and 0:41:32.680 --> 0:41:36.480 they released Wolbachia infected mosquitoes and it reduced the spread 0:41:36.520 --> 0:41:38.440 of dengay by seventy seven percent. 0:41:38.760 --> 0:41:39.160 Wow. 0:41:39.200 --> 0:41:41.799 So not one hundred percent, but like, man, those are 0:41:41.840 --> 0:41:44.800 much better odds. I'd take those odds. But then I 0:41:44.840 --> 0:41:47.600 found a twenty twenty four review paper that was trying 0:41:47.640 --> 0:41:52.799 to aggregate all of the Wobakia infected mosquito results, and 0:41:52.840 --> 0:41:55.160 they reported that essentially the only paper they were able 0:41:55.200 --> 0:41:57.759 to find was this paper from Indonesia. There were two 0:41:57.840 --> 0:42:01.319 other ongoing studies collecting data, but they hadn't published results yet. 0:42:01.800 --> 0:42:03.400 And so I would say at this point that this 0:42:03.480 --> 0:42:06.359 is super promising. I'd like to see evidence that it's 0:42:06.400 --> 0:42:09.400 working in some other areas before I could say like, ah, we. 0:42:09.719 --> 0:42:11.160 This is this might be the key. 0:42:11.920 --> 0:42:15.920 But for dengay, there's some preliminary evidence that this method 0:42:16.080 --> 0:42:16.719 is promising. 0:42:16.920 --> 0:42:19.960 Well, I'm a big fan of anything that's anti mosquito, 0:42:20.560 --> 0:42:22.839 and I'm a big fan of preventing dengay or other 0:42:22.920 --> 0:42:26.160 kinds of diseases, but the idea of like intentionally infecting 0:42:26.280 --> 0:42:30.000 mosquitoes with some kind of bacteria seems dangerous, like kind 0:42:30.000 --> 0:42:32.320 of I know this thing is going to like mutate 0:42:32.480 --> 0:42:34.280 and then all of a sudden it's some new horrible 0:42:34.280 --> 0:42:35.760 face melting disease or something. 0:42:36.760 --> 0:42:40.240 So you know, this bacteria is pretty widespread in nature, 0:42:40.320 --> 0:42:44.120 so it's not like we're introducing something super weird into 0:42:44.120 --> 0:42:47.719 the environment, but it is a different strain. I don't know, 0:42:47.880 --> 0:42:48.960 bacteria expert. 0:42:49.000 --> 0:42:51.520 What do you think, Katrina, Well, I guess I was 0:42:51.520 --> 0:42:54.080 just going to say that this Wolbakia bacteria, I think 0:42:54.080 --> 0:42:56.960 it's present in like forty percent of insects, and so 0:42:57.120 --> 0:43:00.040 of course there's going to be very individual relationships that 0:43:00.080 --> 0:43:02.120 each bacteria has with its own insect. 0:43:02.200 --> 0:43:04.040 But I don't know of the things that humans do 0:43:04.160 --> 0:43:08.080 to manipulate the environment, this seems like a relatively innocuous one. 0:43:08.120 --> 0:43:09.160 I think it's really cool. 0:43:09.200 --> 0:43:12.160 It's like not so toxic to just kind of scramble 0:43:12.200 --> 0:43:14.040 things around a little and hope for a better outcome. 0:43:14.320 --> 0:43:16.360 All right, Well, if people's faces get melted, it's on you. 0:43:16.719 --> 0:43:20.960 Oh no, well I think it's on Oxytech, which is 0:43:21.040 --> 0:43:24.120 a company that is releasing some of these mosquitoes. I 0:43:24.160 --> 0:43:26.719 don't know that we can blame Katrina, she didn't release them. 0:43:27.120 --> 0:43:33.120 But thank you for looking up for me. Kelly, Yeah, 0:43:33.200 --> 0:43:35.320 you're welcome. I like when we can team up against 0:43:35.360 --> 0:43:37.760 Daniel so well. 0:43:37.600 --> 0:43:39.640 You know, then maybe I need you to chime in 0:43:39.719 --> 0:43:43.400 on a topic that's been discussed heatedly at the Whites 0:43:43.440 --> 0:43:46.520 and Institute board meetings recently, really, which is you know 0:43:46.560 --> 0:43:48.680 what is the source of all the mosquitoes at the 0:43:48.719 --> 0:43:52.200 Whites and is too compound that are biting Daniel. And 0:43:52.719 --> 0:43:55.759 for example, I'm against having sources of fresh water near 0:43:55.800 --> 0:43:59.240 the house, but Katrina is growing vegetables hydroponically in our backyard. 0:44:00.040 --> 0:44:02.320 H what do you think, Kelly, I need a ruling. 0:44:03.520 --> 0:44:06.359 There's no way for a mosquito to get into this 0:44:06.680 --> 0:44:10.080 hydroponic growth chamber or for a mosquito to get out, 0:44:10.120 --> 0:44:12.040 so I just really don't think it's possible for them 0:44:12.040 --> 0:44:13.960 to be in there. But there is sometimes like a 0:44:14.000 --> 0:44:17.040 bowl of water that collects from rain that I don't notice, 0:44:17.239 --> 0:44:20.720 and I'm sorry if that caused any mosquito growing to happen. 0:44:21.120 --> 0:44:24.080 I mean, I'm hearing all of your fancy engineering explanations 0:44:24.080 --> 0:44:26.400 for why this can't happen, but I'm taking measurements of 0:44:26.400 --> 0:44:29.160 mosquito bites and I'm telling you it's high. 0:44:29.320 --> 0:44:31.600 It feels like there's been a lot of mosquitoes lately. 0:44:31.640 --> 0:44:34.440 But I thought we could blame that shipping container of 0:44:34.520 --> 0:44:36.160 the Port of Long Beach. Isn't that why? 0:44:36.440 --> 0:44:37.400 Well, what do you think, Kelly? 0:44:38.440 --> 0:44:41.279 I think that I like every opportunity that I can 0:44:41.320 --> 0:44:45.680 have to side with Katrina, But I don't really want 0:44:45.719 --> 0:44:47.360 to get in the middle of a marital spat, so 0:44:47.400 --> 0:44:49.840 I'm going to run away and call a commercial break 0:44:50.000 --> 0:44:51.319 and pretend none of this happened. 0:44:51.360 --> 0:45:15.000 When we get back, and we're back and we are talking. 0:45:14.840 --> 0:45:19.880 About genetic engineering techniques for controlling mosquito populations. This time around, 0:45:20.120 --> 0:45:22.000 we're about to get to gene drives, which was the 0:45:22.000 --> 0:45:24.879 listener's question. This is the most roundabout way of getting there. 0:45:25.239 --> 0:45:28.520 But first let's talk about some genetic engineering where essentially 0:45:28.600 --> 0:45:30.920 you take males and you make it so that if 0:45:30.960 --> 0:45:34.759 they don't encounter tetracycline, they will die. 0:45:34.960 --> 0:45:35.919 What is tetracycline. 0:45:36.000 --> 0:45:39.520 Tetracycline is an antibiotic, and essentially you make it so 0:45:39.600 --> 0:45:43.680 that the males are making a protein that when it's 0:45:43.719 --> 0:45:47.319 made it messes up the cells activity. But in the 0:45:47.360 --> 0:45:51.720 presence of tetracycline, that protein is suppressed so it doesn't 0:45:51.760 --> 0:45:55.000 get made. So males in the lab are given tetracycline, 0:45:55.040 --> 0:45:58.280 they act normal, but when they produce suns in the wild, 0:45:58.480 --> 0:46:01.640 the suns start producing this protein like crazy. It messes 0:46:01.719 --> 0:46:04.200 up their cell activity and they die. And so the 0:46:04.239 --> 0:46:07.280 females do lay eggs but their eggs don't tend to survive. 0:46:07.600 --> 0:46:10.560 So you genetically engineer mosquitos to be dependent on this 0:46:10.640 --> 0:46:12.680 thing that you can give them. So when they go 0:46:12.719 --> 0:46:15.440 out there in the wild, their bodies are making this 0:46:15.520 --> 0:46:18.960 protein and since they don't have this magic powder, they 0:46:19.040 --> 0:46:20.120 end up killing themselves. 0:46:20.320 --> 0:46:21.319 They end up dying. Yeah. 0:46:21.320 --> 0:46:21.560 Wow. 0:46:21.680 --> 0:46:25.120 These are pretty complicated strategies, and they also are strategies 0:46:25.120 --> 0:46:28.319 that tend to make a lot of people uncomfortable. So, 0:46:28.680 --> 0:46:32.480 for example, this has been tried in the Cayman Islands, Panama, Brazil, 0:46:32.840 --> 0:46:36.000 and Florida, and in the Florida Keys, for example, the 0:46:36.040 --> 0:46:40.120 initial response was like massive backlash against the release of 0:46:40.200 --> 0:46:43.560 these GMO mosquitoes. They ended up getting released anyway, but 0:46:43.600 --> 0:46:45.720 there were people who were saying like, I'm gonna find 0:46:45.840 --> 0:46:48.640 the boxes where there's these mosquitos are supposed to hatch from, 0:46:48.680 --> 0:46:51.399 and I'm gonna dump them out or pour bleach in them. 0:46:51.440 --> 0:46:54.279 And I think in general it's really important that you 0:46:54.360 --> 0:46:56.640 have public buy in for these sorts of things, because 0:46:56.680 --> 0:46:59.120 otherwise you just get you know, you get people who 0:46:59.160 --> 0:47:02.279 are justifiably upset. They don't understand what's being released. They're 0:47:02.320 --> 0:47:04.560 worried that the genes that got put in the mosquitoes 0:47:04.640 --> 0:47:05.520 might jump into them. 0:47:06.040 --> 0:47:08.279 Is that what the concern is that the that they're 0:47:08.280 --> 0:47:10.600 going to end up depending on tetracyclin also or is 0:47:10.640 --> 0:47:14.440 it just a generic like I'm scared of GMO stuff. 0:47:14.600 --> 0:47:16.319 I think it's more of a generic. I'm scared of 0:47:16.320 --> 0:47:18.960 GMO stuff. You know, folks don't want GMO foods. I 0:47:18.960 --> 0:47:21.040 think they don't necessarily like the idea of getting bitten 0:47:21.040 --> 0:47:22.279 by GMO mosquitos. 0:47:22.600 --> 0:47:25.600 I think they also don't like the idea of putting 0:47:25.600 --> 0:47:28.640 an engineered gene out in the environment and not knowing 0:47:28.640 --> 0:47:33.160 where it's going to end. So like these island capture experiments, 0:47:33.160 --> 0:47:34.880 where of course the idea is that it's an island 0:47:34.920 --> 0:47:38.759 so it's somewhat contained, are still unsettling because the world 0:47:38.800 --> 0:47:40.799 is so connected right now, so it's hard to know 0:47:40.840 --> 0:47:42.520 what the reach of an experiment like that. 0:47:42.560 --> 0:47:43.719 Will be exactly. 0:47:43.760 --> 0:47:47.319 And so while these releases do first have to go 0:47:47.360 --> 0:47:51.560 through like a complicated series of approvals through groups like 0:47:52.280 --> 0:47:56.000 the Food and Drug Administration, the United States Department of Agriculture, 0:47:56.160 --> 0:48:00.000 the Environmental Protection Agency, it is still the first time 0:48:00.080 --> 0:48:03.439 we're doing something like this, and so ox Tech did 0:48:03.520 --> 0:48:08.160 release mosquitos that had this tetracycling thing happening, and some 0:48:08.239 --> 0:48:12.360 of the genes from the mosquitoes did end up being 0:48:12.400 --> 0:48:15.800 found in wild mosquito, so like those genes had escaped 0:48:15.840 --> 0:48:19.239 into the population. There were some headlines at the time 0:48:19.360 --> 0:48:21.960 that sort of were way overblown. They said things like, 0:48:22.000 --> 0:48:25.160 these genes are going to make the wild mosquitoes even 0:48:25.280 --> 0:48:27.319 better at biting us, and now we've just made our 0:48:27.360 --> 0:48:30.759 problem worse. There wasn't necessarily any evidence for that, but 0:48:30.840 --> 0:48:34.319 there was evidence that genes that were essentially manufactured in 0:48:34.360 --> 0:48:37.160 a lab are now part of the wild population and 0:48:37.239 --> 0:48:40.359 might be there forever. And we don't really understand if 0:48:40.360 --> 0:48:42.319 that is going to do anything at all. 0:48:42.719 --> 0:48:45.279 I understand the concern that these genes that you've put 0:48:45.280 --> 0:48:47.560 into one mosquito might end up in a wild mosquito, 0:48:47.600 --> 0:48:49.600 and you don't know exactly what's going to happen. Maybe 0:48:49.600 --> 0:48:53.000 it turns them into incredible hulk mosquitos, whatever. But how 0:48:53.000 --> 0:48:56.000 does a gene go from that mosquito to the wild mosquitos. 0:48:56.040 --> 0:48:58.120 Does it have to breed with those mosquitoes or is 0:48:58.160 --> 0:49:00.440 there some other weird horizontal thing happening. 0:49:00.520 --> 0:49:02.000 So I think what happened in this case is that 0:49:02.040 --> 0:49:04.600 one of the mosquito babies that was supposed to die 0:49:04.840 --> 0:49:08.840 did not, and so it survived, had some of the 0:49:08.920 --> 0:49:12.239 genes that it got from its genetically engineered dad, and 0:49:12.280 --> 0:49:14.920 then is passing that through the generation. 0:49:15.239 --> 0:49:16.480 Okay, so it's through breeding. 0:49:16.680 --> 0:49:19.520 Yeah, you could imagine some compensation that allowed it to 0:49:19.560 --> 0:49:24.360 survive with that toxic protein, and then the toxic protein 0:49:24.400 --> 0:49:27.440 would stick in the population. I mean, I guess in 0:49:27.480 --> 0:49:30.840 my mind, there's so much evolution and transfer of genetic 0:49:30.920 --> 0:49:34.920 material all the time that any tiny little drop that 0:49:34.960 --> 0:49:38.440 comes from a lab feels insignificant to me. But I 0:49:38.480 --> 0:49:41.040 do understand why it feels unsettling. 0:49:41.120 --> 0:49:44.520 That's my gut feeling. Also, like horizontal gene transfer happens 0:49:44.560 --> 0:49:47.200 between insects and our food, and just all sorts of 0:49:47.200 --> 0:49:50.359 different transfers are happening all the time in nature. I'm 0:49:50.440 --> 0:49:54.120 less worried about a genetic sequence that seems pretty benign 0:49:54.400 --> 0:49:56.040 getting out into the wild. But on the other hand, 0:49:56.120 --> 0:49:59.720 I'm somebody who is totally fine eating genetically modified foods. 0:50:00.120 --> 0:50:02.839 But I understand that that's not true for everybody, and 0:50:02.920 --> 0:50:05.080 so I can understand why this would be upsetting to 0:50:05.480 --> 0:50:05.960 some people. 0:50:06.080 --> 0:50:09.320 I think generally, you know, biologists don't know how everything works, 0:50:09.440 --> 0:50:12.040 and we're pushing buttons and pulling levers on a big, 0:50:12.080 --> 0:50:15.520 complicated machine, and it does feel like one little button 0:50:15.560 --> 0:50:17.960 on a huge machine. But you know, you release the 0:50:18.040 --> 0:50:21.080 right pathogen and it can definitely have a big impact 0:50:21.120 --> 0:50:21.760 on a population. 0:50:22.120 --> 0:50:23.640 Yeah, I think it's important to be humble. 0:50:23.760 --> 0:50:26.160 Yeah, So let's get to gene drives, which is probably 0:50:26.200 --> 0:50:28.880 the most like ethically controversial thing that we'll be talking 0:50:28.880 --> 0:50:32.320 about today. And you know, we bring Katrina on the 0:50:32.320 --> 0:50:35.920 show because we generally love Katrina's input, but she also 0:50:36.000 --> 0:50:38.640 understands gene drives. And I spent a day smashing my 0:50:38.760 --> 0:50:42.320 head against a paper I could not understand. And so Katrina, 0:50:42.440 --> 0:50:44.360 could you explain gene drives for us, please? 0:50:44.640 --> 0:50:48.400 So, a gene drive refers to when you use genetic 0:50:48.480 --> 0:50:52.200 engineering to force a gene through a population at a 0:50:52.239 --> 0:50:56.760 really high rate. So normally our genes are inherited approximately 0:50:56.800 --> 0:51:00.000 fifty to fifty, so the chances of inheriting a pertinent 0:51:00.400 --> 0:51:04.400 trait are not weighted in one direction or another. What 0:51:04.440 --> 0:51:07.680 a gene drive does is it ensures or drives that 0:51:07.800 --> 0:51:11.000 a particular trait will be more frequent in the population 0:51:11.719 --> 0:51:14.360 and so, and we've actually been using this technique in 0:51:14.400 --> 0:51:17.760 the context of mosquitos with a few different strategies in mind. 0:51:17.880 --> 0:51:20.719 This it could be something that affects fertility, so then 0:51:20.760 --> 0:51:24.399 you drive the population to extinction, So that would lead 0:51:24.440 --> 0:51:27.799 to you know, fewer mosquitos is the goal there. But 0:51:27.920 --> 0:51:31.200 then there's also strategies where you try to prevent the 0:51:31.280 --> 0:51:35.160 mosquitoes from spreading malaria. So there's some mosquitos that are 0:51:35.239 --> 0:51:38.640 naturally resistant to carrying the malaria parasite, and so spreading 0:51:38.640 --> 0:51:41.440 that strategy is another gene drive technique. 0:51:41.600 --> 0:51:43.680 So can we dig a bit deeper, Like I understand 0:51:43.840 --> 0:51:46.600 sort of the basics of genetics at the sort of 0:51:46.600 --> 0:51:50.080 pea pod level, you know from Gregor Mendel, and you 0:51:50.400 --> 0:51:52.359 have a fifty percent chance of getting the gene from 0:51:52.400 --> 0:51:54.879 one parent or from the other. How does the gene 0:51:54.960 --> 0:51:57.839 drive affect which genes you're going to end up with? 0:51:58.000 --> 0:52:00.799 Well, okay, the one really cool strategy that people use 0:52:00.960 --> 0:52:05.240 to make gene drives work is to borrow the phage 0:52:05.239 --> 0:52:09.000 defense system called Crisper cast nine. As you guys hopefully 0:52:09.040 --> 0:52:12.080 know all about, there are these viruses called phages that 0:52:12.080 --> 0:52:16.920 can infect bacteria and the bacteria defund themselves in all 0:52:17.000 --> 0:52:20.239 kinds of interesting ways, and one of them has been 0:52:20.280 --> 0:52:23.520 co opted for all kinds of genetic engineering. It's called 0:52:23.560 --> 0:52:27.480 Crisper cast nine, and it turns out whenever the phage 0:52:27.600 --> 0:52:31.960 infect the bacteria, the bacteria keep a little record of 0:52:32.160 --> 0:52:35.240 little snippets of the genes that the phage was trying 0:52:35.280 --> 0:52:38.360 to infect the bacteria with. And then they put a 0:52:38.360 --> 0:52:41.320 little pair of scissors, a gene that can chop DNA 0:52:41.400 --> 0:52:44.040 up next to the little memory bank of all the 0:52:44.040 --> 0:52:47.319 little phage genes that were left behind. And then when 0:52:47.360 --> 0:52:50.960 the phage tries to infect the scissors, the gene that 0:52:51.000 --> 0:52:54.279 has the DNA cutting enzyme on it will match up 0:52:54.360 --> 0:52:57.879 with the pieces of the phage gene and it'll chop 0:52:58.000 --> 0:53:00.600 up the phage as it tries to enter. The Nobel 0:53:00.600 --> 0:53:05.880 Prize last year to Jennifer Dawna and Manuel Sharpentier because 0:53:05.960 --> 0:53:09.520 they had the idea of taking this tool and using 0:53:09.560 --> 0:53:13.080 it to engineer genes in any system. 0:53:13.280 --> 0:53:15.080 So, just to back up and make sure we're understanding, 0:53:15.280 --> 0:53:18.760 the Crisper idea is some sort of like bacterial immune 0:53:18.760 --> 0:53:22.160 system where it remembers the viruses it's seen before and 0:53:22.280 --> 0:53:25.080 has a bunch of guys floating around which will recognize 0:53:25.120 --> 0:53:27.759 those viruses. Plus it comes with scissors so that when 0:53:27.760 --> 0:53:30.640 the viruses come near, it latches on and then it 0:53:30.680 --> 0:53:32.880 chops them up and then the viruses can't infect the 0:53:33.080 --> 0:53:37.160 bacteria anymore. So the basics of how the Crisper system works, yeah. 0:53:36.920 --> 0:53:39.200 That is exactly the basics. 0:53:39.719 --> 0:53:42.799 But the idea of using it as a tool is 0:53:42.880 --> 0:53:46.520 really cool because basically, now you have a system that 0:53:46.640 --> 0:53:50.120 can go and find a particular DNA sequence and then 0:53:50.160 --> 0:53:51.960 it's got scissors right next to it, so it can 0:53:52.000 --> 0:53:56.239 go cleanly chop things out exactly next to whatever sequence is. 0:53:56.200 --> 0:53:56.759 Next to it. 0:53:57.200 --> 0:54:00.680 So with the phases, the bacteria using it to chop 0:54:00.800 --> 0:54:03.480 up phages. But now imagine you wanted to go in 0:54:03.520 --> 0:54:06.080 there and slice and dice a mutation that was causing 0:54:06.080 --> 0:54:07.080 sickle cell anemia. 0:54:07.640 --> 0:54:08.359 You can do that. 0:54:08.360 --> 0:54:11.480 That actually is happening in people right now, which is amazing. 0:54:11.560 --> 0:54:15.760 So people with sickle selenemia now can have some access 0:54:15.840 --> 0:54:20.040 to Crisper CAST nine genetic engineering technology where you use 0:54:20.080 --> 0:54:22.080 the same scissors, but this time you match it to 0:54:22.120 --> 0:54:25.040 the gene causing the sickle cell disease and you have 0:54:25.160 --> 0:54:28.520 the scissors go in there and snip out the problematic 0:54:28.600 --> 0:54:32.120 gene and replace it with a healthy gene. And I mean, 0:54:32.160 --> 0:54:35.800 that's to me amazing that that is actually working in people. 0:54:36.600 --> 0:54:39.280 The idea is not that old. I mean the discovery 0:54:39.320 --> 0:54:42.759 is somewhat recent. And so that's the same strategy that's 0:54:42.760 --> 0:54:46.360 been used to build mosquito gene drives. 0:54:46.600 --> 0:54:50.120 So I understand how Crisper can let you edit your genes, 0:54:50.640 --> 0:54:52.880 which on one hand sounds like why is that are 0:54:53.040 --> 0:54:55.040 you know, you just like go in and edit the data. 0:54:55.120 --> 0:54:57.640 But like this data stored on DNA, you can't just 0:54:57.680 --> 0:54:59.480 go in there and like manipulate it with tweezers. You 0:54:59.520 --> 0:55:03.319 need some of like microscopic manipulation tools, and that's what 0:55:03.400 --> 0:55:05.800 Crisper is giving you. But how does that connect to 0:55:05.880 --> 0:55:09.240 gene drives. How does Crisper let you enhance which genes 0:55:09.280 --> 0:55:10.600 get passed down in the population. 0:55:11.040 --> 0:55:15.520 Well, you engineer mosquitos that contain a Crisper cast nine 0:55:15.600 --> 0:55:19.279 gene set in there. And so you could put the 0:55:19.320 --> 0:55:23.160 scissors right next to a gene that's important for fertility, 0:55:23.680 --> 0:55:25.799 or you could put the scissors right next to a 0:55:25.840 --> 0:55:29.680 gene that controls whether the mosquito is able to be 0:55:30.480 --> 0:55:34.239 infected by the malaria parasite, and so if you put 0:55:34.239 --> 0:55:38.000 that in there, then the crisper cast nine scissors will 0:55:38.000 --> 0:55:43.120 go around spreading that gene even after the mosquito is born, 0:55:43.440 --> 0:55:47.279 so it's throughout the mosquito's life the gene drive will 0:55:47.320 --> 0:55:51.080 be active and it will continue to spread that gene. 0:55:51.080 --> 0:55:55.320 So your opportunity for picking up your genetic traits will 0:55:55.760 --> 0:55:58.799 not end right at the moment of Mendelian inheritance. 0:55:59.000 --> 0:56:01.359 The gene drive will can continued to be active after. 0:56:01.600 --> 0:56:04.200 Oh, in the same way that you go in and 0:56:04.320 --> 0:56:07.600 edit somebody's genes when they're alive to remove the bit 0:56:07.680 --> 0:56:11.520 that's giving them some condition, you're basically giving these mosquitoes 0:56:11.719 --> 0:56:14.759 a little bit of genetic engineering during their whole lifetime, 0:56:15.120 --> 0:56:17.520 so it's not just what they inherit. You're like changing 0:56:17.560 --> 0:56:19.040 them after the fact. That's cool. 0:56:19.719 --> 0:56:22.359 Yeah, So basically, if that gene drive is in there, 0:56:22.520 --> 0:56:25.759 every time the little cassette that has the scissors on 0:56:25.800 --> 0:56:29.360 it encounters the gene that it can match to, it 0:56:29.400 --> 0:56:33.239 will swap things around, so you can. Like one of 0:56:33.239 --> 0:56:35.480 the examples that I really loved that I read about 0:56:36.120 --> 0:56:39.640 was where they had a naturally malaria or resistant mosquito, 0:56:40.200 --> 0:56:42.600 and it was just caused by one snip and a gene, 0:56:42.960 --> 0:56:46.279 a single mutation, and they made a gene drive that 0:56:46.680 --> 0:56:50.239 forced that mutation through the population. But it's it's a 0:56:50.320 --> 0:56:55.479 naturally existing gene, so they're not making a Frankenstein mosquito here, 0:56:56.000 --> 0:57:00.319 and it made it so that the malaria infectivity rate 0:57:00.360 --> 0:57:02.239 of the mosquito population could go down. 0:57:02.480 --> 0:57:04.360 I found another paper where they were tinkering with the 0:57:04.360 --> 0:57:07.840 gene that they called double sex, and essentially what happened 0:57:07.880 --> 0:57:10.200 is they made sure, you know that everybody got two 0:57:10.320 --> 0:57:13.360 versions of double sex, and if you're a female that 0:57:13.480 --> 0:57:16.960 has the double sex genes, you are sterile and you 0:57:17.080 --> 0:57:20.080 also look a little bit male like. But males who 0:57:20.120 --> 0:57:22.560 get it are normal and they can go on spreading 0:57:22.560 --> 0:57:25.960 the gene drive. So essentially every baby that's produced that's 0:57:25.960 --> 0:57:28.360 a female is not going to make any more babies, 0:57:28.680 --> 0:57:30.640 and males that are produced are going to be able 0:57:30.640 --> 0:57:32.560 to go on in mate, but they're going to pass 0:57:33.040 --> 0:57:37.640 this gene drive onto their offspring, and so they'll create 0:57:37.720 --> 0:57:40.480 female babies that die and male babies that go off 0:57:40.480 --> 0:57:43.280 and continue to pass the gene drive until it gets 0:57:43.280 --> 0:57:46.760 through essentially the entire population. I think is the goal. Wow, 0:57:46.800 --> 0:57:51.320 well yeah, and so this has not yet been released 0:57:51.360 --> 0:57:54.640 into the environment, and so, as Katrina noted, there's two 0:57:54.640 --> 0:57:57.280 different methods. You could try to either kill the mosquitoes directly, 0:57:57.400 --> 0:57:59.080 or you could do something to the mosquito so they 0:57:59.120 --> 0:58:01.600 can't transmit the dizzy anymore. There might be some other 0:58:01.640 --> 0:58:03.240 options too, but those are the two things that people 0:58:03.240 --> 0:58:06.280 are working on right now. But this, I think this 0:58:06.400 --> 0:58:11.480 technique in particular, is a little scarier ecologically because you know, like, 0:58:11.560 --> 0:58:14.880 what if that gene drive jumps to I don't know, 0:58:14.920 --> 0:58:19.800 another mosquito species. Maybe having two mosquito species eradicated doesn't 0:58:19.800 --> 0:58:22.880 sound so bad, but what if somehow that gene drive 0:58:22.960 --> 0:58:26.080 is able to jump to I don't know, a ladybug 0:58:26.120 --> 0:58:29.840 that helps control pests in agriculture or something. And now 0:58:29.880 --> 0:58:32.000 we've got this thing that could lead to extinction, and 0:58:32.000 --> 0:58:35.240 there's some concern that if you release it, you know, 0:58:35.280 --> 0:58:36.360 where is it going to end up? 0:58:36.600 --> 0:58:38.800 But how do these jumps happen? Earlier we were saying 0:58:39.280 --> 0:58:42.800 that the genetic engineering that you manufacturing your mosquitos can 0:58:42.840 --> 0:58:46.000 spread to wild mosquitoes through inheritance, But we're not having 0:58:46.040 --> 0:58:50.080 mosquitoes like having babies with ladybugs. How does that jump possible? 0:58:50.200 --> 0:58:52.000 So, as we're going to talk about in a future episode, 0:58:52.000 --> 0:58:55.680 the definition of a species isn't always entirely crisp. Sometimes 0:58:55.680 --> 0:58:58.200 you can get you know, individuals that are in the 0:58:58.200 --> 0:59:00.640 same genus, for example, mating with each I don't know 0:59:00.680 --> 0:59:03.919 if they get confused or they have very particular interests 0:59:04.320 --> 0:59:05.800 something they're looking for in a partner. 0:59:05.920 --> 0:59:08.400 No judge, but no judgment, no judgment. 0:59:08.440 --> 0:59:12.080 But if you know the mosquito species, you put the 0:59:12.080 --> 0:59:15.480 gene drive in mates with another mosquito species. Now you're 0:59:15.520 --> 0:59:17.120 wiping out that species too. 0:59:17.280 --> 0:59:17.960 And you can. 0:59:17.840 --> 0:59:22.000 Imagine yourself jumping around the tree of life and whenever 0:59:22.080 --> 0:59:25.200 you get some you know, cross species mating, you've now 0:59:25.240 --> 0:59:26.800 got that species wiped out too. 0:59:27.000 --> 0:59:29.680 So crisper can move because species aren't crisp, is what 0:59:29.720 --> 0:59:30.240 you're telling me. 0:59:30.440 --> 0:59:34.040 Ah, that's right, I mean, yeah, that's definitely. 0:59:34.040 --> 0:59:37.920 One way is through mating partners that might be a 0:59:37.920 --> 0:59:41.600 little bit less related. But I mean another big strategy 0:59:41.880 --> 0:59:45.800 is sometimes there are big leaps in genes that get 0:59:45.840 --> 0:59:48.960 transferred across the tree of life, and that often is 0:59:49.080 --> 0:59:53.520 facilitated by viruses. So, for example, eight percent of the 0:59:53.600 --> 0:59:57.240 human genome is in the form of endogenous retroviruses. So 0:59:57.280 --> 1:00:01.560 that means that one of our long ago ancestors had 1:00:01.560 --> 1:00:04.880 a virus infect one of their germline cells, one of 1:00:04.880 --> 1:00:07.240 their sex cells, and we have inherited that to the 1:00:07.280 --> 1:00:10.080 tune of literally eight percent of our genome. Most of 1:00:10.120 --> 1:00:12.840 them are pretty dormant and haven't really affected us that much, 1:00:13.120 --> 1:00:15.480 but some of them have led to the biggest innovations 1:00:15.480 --> 1:00:18.640 in biology. So like, for example, did you guys know 1:00:19.240 --> 1:00:23.120 that the gene that led to the placenta evolving came 1:00:23.120 --> 1:00:27.280 from a virus? So an endogenous retrovirus that infected one 1:00:27.280 --> 1:00:32.880 of our ancestors back before mammals existed, had a gene 1:00:32.880 --> 1:00:36.520 in it that helps with membrane fusion. So like that 1:00:36.600 --> 1:00:38.919 gene in a virus is great for helping the cell 1:00:38.960 --> 1:00:42.840 membrane fusee but in a mammal it allows for the 1:00:42.880 --> 1:00:45.880 fusion between the uterus and the placenta cool, so those 1:00:45.960 --> 1:00:49.040 kind of jumps can happen. And to me, that's a 1:00:49.120 --> 1:00:53.320 really big question about gene drives because what if this 1:00:53.440 --> 1:00:58.680 crisper gene gets transmitted farther afield. I think that's the 1:00:58.720 --> 1:01:01.400 real concern, But keep in mind, in your own gut. 1:01:01.480 --> 1:01:04.840 Right now, you have thousands of bacteria that contain all 1:01:04.920 --> 1:01:08.040 kinds of crisper systems, and I'm not worried about those 1:01:08.080 --> 1:01:09.600 transmitting into human cells. 1:01:09.880 --> 1:01:11.760 And I should note there are labs that are working 1:01:11.800 --> 1:01:14.800 on anti gene drive techniques, like a gene that you 1:01:14.840 --> 1:01:17.080 could release into the population that would sort of stop 1:01:17.160 --> 1:01:19.480 the gene drive. And so there are some folks who 1:01:19.520 --> 1:01:22.280 are forward thinking about this problem and are trying to 1:01:22.280 --> 1:01:25.200 stop it. But then we can return to Daniel's earlier point, 1:01:25.200 --> 1:01:28.680 which is that biology is complicated and biologists don't necessarily 1:01:28.720 --> 1:01:30.640 know what's going to happen. So, like, what if we 1:01:30.720 --> 1:01:34.640 knock out one mosquito species, a different mosquito species fills 1:01:34.680 --> 1:01:37.840 that niche, and that species is even better at transmitting 1:01:37.880 --> 1:01:40.640 the disease. Now we've you know, maybe we can release 1:01:40.680 --> 1:01:43.360 gene drives again to control the problem. But like, it's 1:01:43.400 --> 1:01:45.160 hard to know what's going to happen to a system 1:01:45.200 --> 1:01:48.600 when you remove an animal that has you know, a 1:01:48.680 --> 1:01:51.520 large number of individuals out in the population, and we 1:01:51.560 --> 1:01:55.240 don't really understand the ecological impacts. So Daniel mentioned that 1:01:55.320 --> 1:01:59.400 some mosquitoes pollinate chocolate, you know, may what if you 1:01:59.440 --> 1:02:01.680 have a mosquite species that ends up being an important 1:02:01.680 --> 1:02:04.840 food source, for example, for a fish species that is 1:02:04.840 --> 1:02:08.560 an important source of protein for the local community. So like, 1:02:08.600 --> 1:02:11.320 there's a lot of you know, ecological stuff that might 1:02:11.360 --> 1:02:14.160 happen that we don't understand very well. And so making 1:02:14.160 --> 1:02:17.720 the decision to knock out a species because we've decided 1:02:17.720 --> 1:02:19.760 we wanted to do that, you know, could have some 1:02:19.800 --> 1:02:21.720 other implications. But if, on the other hand, you're talking 1:02:21.760 --> 1:02:23.880 about you know, more than half a million people dying 1:02:23.920 --> 1:02:27.480 every year from malaria, my tolerance for taking risks goes 1:02:27.560 --> 1:02:29.560 up a little bit. But those risks should be well 1:02:29.600 --> 1:02:31.560 thought through, in my opinion, and I hope that. 1:02:31.560 --> 1:02:34.640 You're including my itchy ankles from mosquito bytes in your calculation. 1:02:34.840 --> 1:02:36.040 I'm not away a lot. 1:02:36.280 --> 1:02:37.000 I'm not no. 1:02:39.280 --> 1:02:40.920 And of course Kitchen is going to vote. We do 1:02:41.080 --> 1:02:42.080 so on that voted again. 1:02:44.400 --> 1:02:46.360 So where we are on this right now is that 1:02:46.600 --> 1:02:50.360 some genetically modified mosquitoes have been released and we're doing 1:02:50.400 --> 1:02:53.880 tests on those, but no gene drive mosquitoes have been 1:02:53.960 --> 1:02:57.120 released yet. There was a target malaria was working in 1:02:57.160 --> 1:03:00.360 Bikina Fassa to try to get community buy in, to 1:03:00.440 --> 1:03:03.320 get people on board with this idea of releasing gene drives, 1:03:03.680 --> 1:03:07.200 but recently their facility was essentially rated and they were 1:03:07.200 --> 1:03:09.560 told that their project is being shut down. It was 1:03:09.600 --> 1:03:12.000 a little bit unclear what happened because it seemed like 1:03:12.000 --> 1:03:14.520 the Target Malaria group was in good with the local community, 1:03:14.560 --> 1:03:17.200 in good with the government. There have been some like 1:03:17.280 --> 1:03:20.880 think tanks that think that the problem actually is Russian disinformation, 1:03:21.120 --> 1:03:23.600 where this message has been spread that we are using 1:03:23.640 --> 1:03:27.760 genetic modification to make people sterile, and you know, releasing 1:03:27.800 --> 1:03:31.280 these genetic mosquitos will sterilize the local population. So it 1:03:31.320 --> 1:03:37.120 has become a complicated ethical, geopolitical problem, and that's where 1:03:37.120 --> 1:03:39.240 we are right now. We are sort of trying to 1:03:39.240 --> 1:03:41.720 decide as a society what we're going to do when 1:03:41.760 --> 1:03:44.200 we have this technique that could be used to save 1:03:44.200 --> 1:03:47.040 a bunch of lives from malaria, but has you know, 1:03:47.320 --> 1:03:50.040 potential implications, some of which we know about and some 1:03:50.120 --> 1:03:53.160 of which we might not even understand unless we were 1:03:53.160 --> 1:03:54.560 to actually try the experiment. 1:03:55.080 --> 1:03:57.760 So it's complicated because it's biology, but. 1:03:57.800 --> 1:04:00.720 It's worthwhile because these are people's lives. It matters. 1:04:00.880 --> 1:04:03.640 Yeah, I think it's so interesting that it's more controversial 1:04:03.680 --> 1:04:06.520 when we understand what we're doing better. I mean, for example, 1:04:06.560 --> 1:04:10.040 in agriculture, we've been selecting for traits for thousands of 1:04:10.160 --> 1:04:13.000 years that have all kinds of ecological impact, and we 1:04:13.040 --> 1:04:15.760 don't find that to be controversial. But as soon as 1:04:15.800 --> 1:04:19.360 we use molecular biology tools to genetically engineer things, it's 1:04:20.000 --> 1:04:23.840 less understandable and somehow scarier, although the implications could be 1:04:23.840 --> 1:04:24.240 the same. 1:04:24.360 --> 1:04:25.720 So I think that's really interesting. 1:04:25.960 --> 1:04:29.200 All right, So we have had a fun, complicated discussion 1:04:29.440 --> 1:04:33.920 about mosquitos and genetic engineering, and Katrina, I have no 1:04:33.960 --> 1:04:35.520 doubt we'll bring you back on the show five or 1:04:35.560 --> 1:04:36.800 six more times before. 1:04:36.560 --> 1:04:38.360 The end of the year, which is only a couple 1:04:38.440 --> 1:04:42.680 weeks off. Thanks for coming back on the show. 1:04:42.800 --> 1:04:44.320 Well, thank you for having me. 1:04:44.760 --> 1:04:47.200 Thank you to our listeners for submitting their questions. Let's 1:04:47.200 --> 1:04:49.040 hear what they had to say about the episode. 1:04:49.280 --> 1:04:52.040 I really appreciate you getting to my question and in 1:04:52.120 --> 1:04:54.920 the most relevant episode. I can't say that I'm entirely 1:04:54.960 --> 1:04:57.680 convinced that the reason gene drives haven't been tested yet 1:04:57.840 --> 1:05:01.400 aren't nefarious. After all, if your goal was eradication and 1:05:01.440 --> 1:05:04.560 you released enough mosquitoes on a small island, and considering 1:05:04.560 --> 1:05:07.320 the length of the mosquito life cycle, how long would 1:05:07.360 --> 1:05:10.840 it take to eradicate the species entirely a short time 1:05:10.920 --> 1:05:13.560 period leaves very little time for the genes to jump. 1:05:14.080 --> 1:05:16.840 If the gene drive did jump species and eradicate another 1:05:16.840 --> 1:05:19.760 species of mosquito, oh why has no native mosquitos to 1:05:19.760 --> 1:05:22.920 worry about? In fact, the six to eight invasive mosquito 1:05:22.960 --> 1:05:25.240 species on the islands would make a great test case 1:05:25.280 --> 1:05:25.960 to see if the. 1:05:25.920 --> 1:05:27.480 Gene drives do jump species. 1:05:28.120 --> 1:05:30.680 Maybe some diligent pesticide use by the ports could keep 1:05:30.680 --> 1:05:35.320 any modified mosquitos from leaving the island before total eradication. Overall, 1:05:35.320 --> 1:05:37.880 it seems much less risky than Uruguay's plan to use 1:05:37.880 --> 1:05:41.360 gene drives to eradicate screw worms. Given the biodiversity of 1:05:41.360 --> 1:05:45.200 South America. Maybe the answer is in Wolbakia, which you covered. 1:05:45.480 --> 1:05:48.080 Perhaps is just less risky. It looks like they started 1:05:48.120 --> 1:05:51.120 attempting to use it to radicate coolx mosquitos on Maui 1:05:51.160 --> 1:05:53.360 to save native birds. Thanks so much. 1:06:00.400 --> 1:06:03.880 Daniel and Kelly's Extraordinary Universe is produced by iHeartRadio. 1:06:04.160 --> 1:06:06.800 We would love to hear from you, We really would. 1:06:06.960 --> 1:06:09.720 We want to know what questions you have about this 1:06:09.920 --> 1:06:11.560 Extraordinary Universe. 1:06:11.680 --> 1:06:14.600 We want to know your thoughts on recent shows, suggestions 1:06:14.640 --> 1:06:15.600 for future shows. 1:06:15.720 --> 1:06:18.080 If you contact us, we will get back to you. 1:06:18.320 --> 1:06:21.840 We really mean it. We answer every message. Email us 1:06:21.880 --> 1:06:25.120 at Questions at Danielankelly. 1:06:24.160 --> 1:06:26.240 Dot org, or you can find us on social media. 1:06:26.360 --> 1:06:30.160 We have accounts on x, Instagram, Blue Sky and on 1:06:30.240 --> 1:06:31.200 all of those platforms. 1:06:31.200 --> 1:06:34.120 You can find us at D and K Universe. 1:06:34.360 --> 1:06:35.920 Don't be shy, write to us