Leslie Vosshall, professor of neurogenetics and behavior at the Rockefeller University, speaks with host Steven Strogatz about her research into how to make a less deadly mosquito. After she shares her thoughts on “dude walls” — the arrayed portraits of white men that often decorate academic institutions — he is moved to action at his own university to foster a more inclusive educational environment. This episode was produced by Camille Petersen and Ellen Horne. Read more at QuantaMagazine.org. Production and original music in this episode by Story Mechanics.
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Steven Strogatz: The last of the screws.
Producer Ellen Horne: The last screw. [DRILLING SOUNDS] All right, Leslie would be proud.
Strogatz: Yes, Leslie. Thank you for setting us on this course.
Steven Strogatz [narration]: When I spoke to Leslie Vosshall, I had no idea that she’d be launching me on a mission that would involve power tools and sneaking around in the math department after hours through Cornell University with my producer, with Ellen.
Strogatz: And now we just have to get the, um, evidence out of the building. [LAUGHS] Okay.
Horne: All right. We did it. That was super easy.
Strogatz: Well, that’s it. So now we’ve done it, and, um, I don’t see any sign of police. I think we’re good. [LAUGHS]
Strogatz: We’ll come back to this mischief. It will all make a lot more sense once you’ve heard what Leslie Vosshall has to say, and come to think of it, it’s actually sort of fitting that my conversation with her led to a nighttime recording because — at an academic institution! — because that’s where my conversation with her started.
Strogatz: So you did radio as — in, in what role?
Leslie Vosshall: I was in the first coeducational class at Columbia University, Columbia College, and I was a new music DJ, and I did “Transfigured Night,” the 1:00 AM to 5:00 AM slot on Friday morning.
Vosshall: And so I — I performed very poorly in whatever the class that was on Friday morning at 9:00 AM.
Strogatz: From Quanta Magazine, this is “The Joy of x.” I’m Steve Strogatz. In this episode, Leslie Vosshall.
Vosshall: Yeah, that’s why I’m deaf. I just spent — I mean, this was in the early ’80s in New York City, where it was just a lot of music, a lot of drugs, a lot of biochemistry.
Strogatz: This is great. Wow, this is true confessions. Did — do you actually — you’re not quite teasing. You’ve been to so many rock events and stuff that you think you might have some hearing impairment?
Vosshall: Yeah, which I think is pretty — that’s pretty good street cred, right?
Strogatz: It definitely is. Uh, wow. Interesting, too, for a person who likes to study sensory systems.
Strogatz: Leslie is a — is a terrific neurobiologist who is especially interested in odor, smell. How does smell work at the molecular level, at the genetic level? You know, what is it to smell something? What — and how — especially she’s interested in studying the sense of smell in a particular organism that most of us despise: mosquitos.
Strogatz: I find it’s often nice to talk to scientists about their early days. Did you play with chemistry sets or something? Were you — did you like animals? What was your story as a kid?
Vosshall: Uh, nepotism. My uncle is a professor at Syracuse University, and he ran a summer lab at the Marine Biological Laboratory on Cape Cod, and different — different nieces and nephews would get in line to work in the summer lab, and — so when I was 16, it was my turn, and I went up and started doing science, and it was great. You know, summer in Woods Hole, there’s the beach, there’s sailing, there’s parties with graduate students, and a lot of really exciting science.
Vosshall: So that was it. From the time I was 16, I had no hesitation whatsoever that I would become a biologist.
Strogatz: This is incredible. But I mean, it suggests that you must have had some interest in science that you were willing to do this in the first place.
Vosshall: Well, you know, I think all children have a latent interest in science. It’s hard to find the child that’s not curious, a child that doesn’t love animals, and so I was firmly in that camp. Yes, I had a chemistry set. Yes, I ordered a perfume kit and concocted really horrible perfumes.
We lived in New Jersey, and so I’d go down to the woods and open up the perfume chemistry kit and mix stuff down in the woods.
Strogatz: [LAUGHS] This is amazing. I — now, maybe it was some kind of gender thing, but I don’t remember ever hearing about a perfume kit, so maybe you should walk me through that. [LAUGHS]
Vosshall: You would get chemistry kits where you could blow stuff up, but there was also a niche. Perfumery is chemistry, so it was a niche toy, I guess. You get this big box with, uh — uh, oils that would be a base, and then a bunch of different — different notes, different vials with liquids in them, different color liquids, and — you know, in retrospect, pretty sophisticated, with instructions for how to make a floral scent, or a masculine scent. I, of course, just threw those instructions away and mixed my own stuff.
Strogatz: [LAUGHS] Good.
Vosshall: And it was fun.
Strogatz: That’s so interesting, because it’s true — you know, like today, I — I wonder if they even sell that because you could imagine people worrying about the insurance problems or kids drinking things they shouldn’t drink or —
Vosshall: I know. Yeah, the —
Strogatz: So they don’t maybe. I don’t know if they do.
Vosshall: I think — I feel sorry for children today because their lives have been so de-risked that there’s no — there’s no fun left. We were much more feral, I think. We just ran around and blew stuff up.
Strogatz: I don’t know. It — it was the good ol’ days when kids could be feral and experiment.
Strogatz: Woods Hole, the place where Leslie spent all those summers, is a big deal in the science world. There’s a bunch of institutes there, lots of researchers. It’s like a mythical place in the world of science, especially for biology. I actually spent summer there myself doing an internship at the Woods Hole Oceanographic Institution, and I was there in the summer of my first year after college. So I was about — let’s see, I think I was about like 21 or 22 years old.
Vosshall: Woods Hole is amazing. You go… I went from a small town in New Jersey where there’s no scientists. I didn’t know a scientist aside from my uncle, and then you go up to Woods Hole, and then there’s just hundreds, hundreds of scientists. Every store is full of scientists. It’s like a magical village. I think any kid who has a chance to spend time there will become a scientist.
Strogatz: Well, I — I like your description with the hundreds of scientists walking around, because that was something when my big brother, who is a lawyer, came to visit with his family, as we’re walking around the streets and going into — there’s a little restaurant I think called The Fish Monger or something like that, and my brother, who was very corporate, said, “Everybody looks really weird in this place.”
Vosshall: And it was a funny collision because of course that’s the major departure point for ferries that go out to Martha’s Vineyard and Nantucket.
Vosshall: And so every time a ferry came in, there would — it would disgorge all of these tourists who would walk down the main street and then collide with all the scientists. It was really — it was a great — a great sociology experiment.
Strogatz: [LAUGHS] Exactly. Wow. But so your uncle didn’t just have you washing test tubes?
Vosshall: It started out — they, they needed a lab helper to wash test tubes, pick up packages, and kind of wipe down the benches, and… So I did that really efficiently, and then I became interested in the experiments, and then they realized that I could be put to work picking up packages, but also doing experiments, and in retrospect, the experiments were really wacky, but we published them, so it was my first soup-to-nuts experience.
Strogatz: Why do you describe the experiments back then as wacky?
Vosshall: Well, the first summer we were looking at sea urchin fertilization. Sea urchin is a classic model organism for cell biology, so I would spend my mornings, um, getting male sea urchins to ejaculate by electrocuting them.
Strogatz: Oh, there you go. [LAUGHS]
Vosshall: And then collect all this —
Strogatz: Wait, sorry, what did you say? How did you get them to ejaculate?
Vosshall: I would have this really low tech — it was just like this big battery, and then two metal leads, and I would just jam the metal leads into the side of the male sea urchin, and then turn the thing on. [IMITATES BUZZING SOUND] And then the poor thing would ejaculate. It was fine, but I would throw it back in the other tank, and then collect the sperm.
Strogatz: [LAUGHS] I see.
Vosshall: And then it was kind of worse for the females. I would just take a big syringe of potassium chloride and — and then just jam the syringe into the female sea urchin, and that pretty much killed her, but as a consequence of that, she would release all of her eggs. That was really mean, but there’s a lot of sea urchins in the sea.
Strogatz: Yeah, I suppose. [LAUGHS]
Vosshall: And then I would mix the egg and sperm together, and the experiment was… Normally, the whole principal of biology is it’s one sperm, one egg. That’s really important, and — so we were discovering that if you put in various concoctions of proteins, you can get something called polyspermy, where you get hundreds of sperm attaching to an egg. So that was really cool. I could order all these different proteins, make concoctions, get the sperm and eggs, mix them, add the proteins, and then see these eggs that had hundreds of sperm attached to them. So cool.
Strogatz: Hmm. But so does the egg only get fertilized by one of them?
Vosshall: You know, the experiment kind of — that’s why in retrospect it was kind of wacky. I don’t exactly understand what we were doing. I think I would go through the whole ejaculation, the egg, mix in the concoction, and then just count the number of sperm attached. We — that was kind of the end of it.
Vosshall: So on the one hand, it was a great introduction to science. On the other hand, I have become more sophisticated since then in asking questions.
Strogatz: Maybe we should start talking about the deadliest animal on Earth. Now, you want to tell us, Leslie, what — what we should be thinking of?
Vosshall: A lot of people guess sharks or rabid dogs. But the actual answer is mosquitos.
Vosshall: So mosquitos kill far more people than any other animal on Earth, and this — what’s the second most deadly animal on Earth?
Strogatz: Hey, you got me. Maybe human beings.
Strogatz: Ah. [LAUGHS]
Vosshall: So — so humans — humans kill about half as many other humans as mosquitos do.
Vosshall: But mosquitos are way out in front.
Strogatz: Now, what about bacteria? We don’t want to call them animals, I suppose, or do we?
Vosshall: I mean, mosquitos kill way more people than any — than any prokaryote.
Strogatz: Okay, so bacterial diseases, no contest.
Vosshall: No contest. Yeah, no contest.
Strogatz: But it’s actually the viruses that are causing the problem, right? They’re transporting viruses?
Vosshall: This is correct. This is correct, or, um, Plasmodium. So these little critters that cause malaria. So yeah, the — the mosquitos are blameless. They’re not trying to kill us, but as part of their normal life cycle, they need human blood. And — so they’re really, really good at transferring pathogens between humans. And — so again, mosquitos by themselves are just annoying, but if they’re infected, then they’re incredibly effective at infecting humans.
Strogatz: What got you started on mosquitos? Did — were you thinking about infectious disease from the beginning or, or some more fundamental biological question or, or what?
Vosshall: Yeah, the — the starting point’s when I was a postdoctoral fellow with Richard Axel at Columbia. Richard is known for his many foundational pieces of science, but probably most recently his discovery of how smell works, a discovery for which he won the Nobel Prize, and — with Linda Buck. So Buck and Axel identified the odorant receptors in mammals, and so my project in his laboratory was to find the odorant receptors in insects.
I started that work in 1993, and in the back of our minds, Richard and I always thought that if we found insect odorant receptors, that would be the entry point to studying mosquitos.
Vosshall: Because mosquitos find us because we smell good.
Vosshall: So the sense of smell of insects is really front and center in how they kill us.
Strogatz: I’m — I’m picking up a theme here, going from you, the teenager, with the perfume kit, to you the more mature scientist thinking about odor.
Vosshall: Yeah, absolutely true. I’m — I’m nuts for perfume. I love —
Vosshall: There are no bad smells. I’m, I’m still — one day I’m going to write a book called There Are No Bad Smells.
Strogatz: Really? [LAUGHS] That will be a hit.
Vosshall: So, I mean, every smell is great. Every smell is great.
Strogatz: Every smell is great. Uh, you’ve used the word receptor. Can you tell us what — what you mean by that?
Vosshall: The reason that we’re able to see things in the world, that we can see color and motion and contrast, is because we have cells in our retina that take in light and color, and the proteins that do that are called receptors. And so in the nose, we also have receptors. These are proteins that detect not light, but they detect chemicals, molecules, and because there are many, many more types of, uh, molecules that have odors, the bet that Buck and Axel made is that there would be many, many, many more receptors for smells than there would be for light, and they were correct.
A typical mammal has between 400 and 2,000 genes that encode for odorant receptors. So it’s the largest gene family in — in most animals, and insects have a lot of odorant receptors also. These are the little machines that are sniffing around for odors that you inhale or that contact, in the case of insect, the antenna. And then they interact. They bind with these smells, and the smells then activate the receptor, and then that tells the mosquito brain, “It is a human. It is really good. Fly toward it and bite it.”
Strogatz: I just — it’s sort of mind blowing to me as a visual mainly animal, which I’m imaging a lot of people would call themselves, either visual or, you know, like auditory people — they use either sight or hearing as their main sense. But this sense of the world that would come through having 2,000 or — anyway, hundreds of — instead of just the seven or eight colors that we talk about in the colors of the rainbow, if I had 200 or 1,000 “colors” that are smells, I mean, it’s weird for us, right? ’Cause our smell — sense of smell is sort of like, I don’t know, what, deactivated? Or was never that good to begin with?
Vosshall: So — yeah, so there’s — there’s this folklore that humans have lost their sense of smell, that we’re visual, and that is just wrong. It’s just completely wrong. So —
Strogatz: Oh good. Thank you for correcting me. [LAUGHTER]
Vosshall: No, I mean, I mean, most — you know, most of the world believes that a lot of it — it’s been — it’s been debunked recently.
Strogatz: Yeah. Really?
Vosshall: The old idea was that the part of the brain that humans use to smell is this vestigial nubbin that was just based on some nonsense science, and investigators at Rutgers had a look recently, and that’s just wrong. Humans have a perfectly respectable part of the brain that, that receives smells, and we certainly have — I mean, you have between 350 and 400 receptors that you can do a lot with.
Vosshall: It’s mostly just that people today — I’m sitting in an odorless room right now.
Vosshall: Most, most of us live in an odorless world. So we just don’t have a lot of experience with smells but we, we do a lot of human smell testing in my laboratory at Rockefeller, and… So we have a front seat to how far you can push humans to tell us that they detect really tiny quantities of smell, and that they’re incredibly good at telling very, very similar smells apart. So I think it’s just —
Strogatz: Is that right? That’s interesting.
Vosshall: I just think it’s — we’re, you know, we’re — we are not giving our nose the respect that it deserves.
Strogatz: I get it. I like it. That’s — I think that’s big news. Maybe not to you.
Vosshall: It — well, I mean, I’m constantly — I’m a proponent for “Come on, be… Respect your nose. Tell your nose that your nose is… Be grateful for your nose.”
Strogatz: [LAUGHS] Is there anything like nose exercises?
Vosshall: Yeah, I mean, you mentioned, you mentioned people who are experts in wine, and I, I mentioned experts in perfumery. A lot of it is just paying attention, so learning to — learning to inhale, learning to enjoy the smells, learning to remember them. So a lot of it is training your nose cognitively. I think a lot of people just don’t pay attention to it.
Vosshall: Like you’ll pay attention to really strong smells that you associate with badness, but I think a lot of people — and again, we mostly live in deodorized environments, people are.
Vosshall: If you wear a lot of perfume or aftershave to work, people — people shame you or avoid you.
Strogatz: That’s true. That, that is true. That, that, it —
Vosshall: Most — most — yeah, most of our food is odorless. All, all, you know, all fruits and vegetables and flowers have been bred to be odorless.
Strogatz: Really, even the fruits and vegetables?
Vosshall: Pretty depressing.
Strogatz: Because they, like… They certainly tell you at the supermarket if you want to figure out if the peach is ready, you know, there’s a certain thing with how to squeeze it, and shouldn’t give too much, but they — it should smell delicious. It even tells me this at the — my local supermarket on the brown bag, on the paper bag.
Vosshall: Yeah, but I mean, good luck. I mean, unless, unless you go to a place where they’re growing real peaches or real bananas, you’ll just, you’ll… I mean, it will feel like a peach, and it will have some vague peach scents, but it’s… They’re basically, you know, they’re basically tennis balls. They just — there’s not a lot in — there’s not a lot in modern, modern food. It’s all been bred out.
Strogatz: [LAUGHS] Really? So is this a GMO thing that we should be —
Strogatz: It’s not that.
Vosshall: It’s just — I mean, traditional, traditional plant breeding, I mean, you — you have your — you have your choice about what kind of… If you’re a geneticist, you have your choice about what kind of stuff you want, and so peaches that ship well and don’t bruise and are beautiful also are tasteless and odorless. So I think it’s just a tradeoff.
Vosshall: And roses — you know, go, go into a florist shop, and if you find a rose that smells like a rose, let me know.
Strogatz: After the break, a new kind of diet pill, the thrilling sensory universe of mosquitos, and an ancient question: Do mosquitos actually love you more than your friend?
Strogatz: Back to the mosquito then. There you were. You said Axel and Buck had — or got people into thinking about the science of smell at this molecular level or genetic level too, and you were one of them.
Vosshall: Yeah, it was an absolute… Yep, and it was an absolute revolution in the field. It was really thrilling to be there at the — at the earliest stages where by just cloning the genes that were responsible for smell, just by having those genes in hand, we immediately had an idea for how smell works. There are hundreds of receptors, and collectively they’re able to scan the whole world of chemical space, and the challenge after that was to figure out how the brain —
Vosshall: — imposes meaning on the things that the receptors are smelling. And so I spent probably the first 20 years, 25 years of my career working on this problem in Drosophila melanogaster, the little kitchen flies that love peaches — back to peaches. So they love, they love yeast that grows on fruit, and — but always in the back of my mind was this… The early, the early passion that Axel and I had that, that we could do something useful with insect smell. And so a few years after I started my lab, the Bill and Melinda Gates Foundation put out a call for high risk, high reward projects, and Axel and I applied for that to try to figure out a way to translate everything we knew about smell in Drosophila to smell in, in the mosquito, and that really pushed the lab toward the public health crisis that mosquitos represent.
Vosshall: So we’d been working in the lab on little, cute Drosophila doing very interesting and important basic biomedical research, but when the Gates Foundation would fly us around the world to Cape Town, to Bangkok, to Arusha, and Kenya, where you actually are in the mix there where stuff is happening, then the interesting basic biomedical work on Drosophila just seemed completely irrelevant to me, and I started making the move to “Let’s become a mosquito lab, and let’s do it quickly.”
Strogatz: You mentioned Drosophila, right, so that’s this — you called it the kitchen fly, the fruit fly. Um, it had been studied since the early 1900s, or maybe even earlier, 18… I don’t know, but it — we know a ton about its genetics, its behavior, its neuroscience. Whereas the mosquito, I take it, is relative — until recently maybe was sort of less studied, less was known?
Vosshall: That’s right, so Drosophila is the workhorse of modern biology and genetics. I’d say almost everything we know about biology, we know from Drosophila. It’s really made a — as an organism, a huge contribution. So at the point that we started, we were in some cases a century behind Drosophila. In some cases, decades behind, and it was an incredibly difficult and risky gambit to pivot the lab from working on Drosophila, where we had a century of tools, and a huge and supportive community and places where you could mail order strains that had different interesting mutations, to just going out into the wilderness where there was nothing. We, we started — we had no mosquitos in the lab. We didn’t know how to grow them. There — we didn’t — there wasn’t really a genome that — that would be a substrate for doing genetics. There were no… CRISPR hadn’t been invented. So it was — it was a really difficult and risky period when we did the pivot, and — which really started in 2008.
So eight years after I started my lab, we, we initiated the pivot where I had one person working on mosquito, and about 15 working on Drosophila, and then as of 2016 my last Drosophila person left the lab, and, um… And so in that, in that about a decade from when we started the pivot until it was complete, we had to do everything ourselves. We had to — we resequenced the genome, we got CRISPR working in the mosquito, and it’s been… The acceleration has been really thrilling even in the last year, and there are many groups who also historically worked in Drosophila who have joined us. And so every time I go to a scientific conference, there are people who take me aside and say, “Okay, how hard is it to do the pivot? How hard is it to set up infrastructure to grow the mosquitos?” And so I’m really seeing it starting from almost nothing to a, a, a field, a big thriving field where stuff is happening.
Strogatz: When you went to sleep at night after thinking, “I’m going to make this pivot,” you know, did you have thoughts of “This, this could, you know, down the road, could help so many tens or hundreds of thousands of people”?
Vosshall: Yeah, absolutely. Even before we really initiated the pivot, when we were still working on Drosophila, I was already completely convinced that we could make some progress.
Vosshall: So I didn’t lose sleep over how important it would be. I did absolutely lose sleep about whether we’d be able to pull it off. So in the early days — also as a lab head… When you, you convince all these people, “It’s going to be great. We’re going to do it. We’re going to change the world,” you can’t — you can’t ever show any doubt or any hesitation that it’s going to work. Even though when I go home and I’d say, “This is never going to work. I have all of the careers of these scientists in my hand, and I have no assurance whatsoever that it’s going to work.” So it was — it was really — it was really hard from, from 2000… We started in 2008 in earnest, and it wasn’t until 2013 that we published our first paper, and so all of the people in that five-year valley of death were —
Vosshall: I give them huge credit for getting on the ride and riding with me. But again, I had to always be like “We got this. It’s no problem.”
Strogatz: She’s brave. That’s really came across. As I got to know her, I thought of her as a risk taker but — but someone who is taking risks for important reasons, who’s trying to solve really important problems, not just doing science as an exercise of going through the motions, publishing papers. I mean, she’s not a careerist who just wants to have a job. She’s really trying to solve important problems of infectious disease and fundamental biological problems about how does — how do our sensory systems work? How does smell work? In, in some of the courageous things that she’s done to go after these important problems, she has changed her direction completely.
Strogatz: You as a responsible mentor and, and lab head… You know, as you say, there’s people’s careers at stake and, and they were very — “sacrificial” may be too strong a word, but those, those early students were very altruistic in a way in that they helped everybody come up to speed.
Vosshall: But I — you know, the trick is that you can’t… They can never know that they’re sacrificial lambs, because I knew it would work. I mean, at heart it had to work because I was, I was putting everything on having the pivot work. So they were really brave. On the other hand, there are many experiments that are easy to do in science that you don’t have to sweat over or lose sleep over. And you will get data, but it will be uninteresting. And, and people that you train to do that, you’re also doing them a disservice because they are doing science that can be done but probably shouldn’t be done, and that’s — that’s the thing I try to convey every day, is that it’s worth taking the risk. Because what are we doing, if you’re just doing — redoing stuff? That’s not interesting.
Strogatz: Yeah. No, I mean, I love what you just said because it’s not like it’s such a glamorous or high paying career. I mean, do science that matters, right? I mean, why, why are you just fooling around? So — and, and also I’ve heard it said that it’s just as easy or difficult to do important science as to do trivial pointless science.
Strogatz: Like, it’s not that the important problems are necessarily intrinsically harder. They — they’re all hard. So do something that, that’s going to make a difference at the end of the day.
Vosshall: Yep. And, and it’s surprising — this should be a really obvious message, but it — it is amazing that it’s — it seems to be non-obvious to many people, but I think that — yeah. That’s the message that I try to get across every day, is — we, we really do have our choice of what kind of science we do, and we have to keep it centered on important and fresh and risky things.
Strogatz: You, you know, you were able to maybe go for five years without publication. You were already pretty established. So I don’t know how risky it felt to you. Did it… Like, you said you were sure it would work. You really were? There was no little part of you that thought, “Maybe I’ve —”
Vosshall: I mean, I should rephrase it. I was not sure it would work. I just — I was sure that it had to work, because if it didn’t — if it didn’t work, then that, that would be the end of my career. So I… It was a — it was a — it was a make-or-break bet on a career. So that’s why, like, it had to work, because if it didn’t, that would be the end of it.
Strogatz: What this reminds me of is a TV show that will strike you — maybe, I don’t know if you watch the kind of junk TV I watch. I shouldn’t call it junk TV. It’s called “Project Runway.” Do you like — do you know “Project Runway?”
Vosshall: I’ve seen it on planes, yeah.
Strogatz: Okay, on planes. So “Project Runway” is about fashion design, and designers compete, you know, but there’s a mentor that used to be on the show named Tim Gunn, who is a great, great teacher, and he works with all the different designers. And one of his catchphrases was “Make it work.” You know, they, they have a short time to do their, their design to make the dress or whatever, and sometimes the materials aren’t working out, or their vision doesn’t come to fruition, but they only have a certain amount of time, and they have to make it work. And this attitude, “Stop complaining, make it work,” is, um —
Vosshall: I love it. I love it. I think those are words to live by.
Strogatz: Yeah, and it sounds like you had that. You, you had that feeling, and you passed that on to your students. They made it work, and it did work.
Strogatz: So yeah, no, let’s get to that good part where it did work. I mean, recently I hear you have some discovery about, uh — from, from what you learned from your basic science, how to feed diet drugs to change the hunger levels of these mosquitos for human blood as a strategy, an interesting strategy.
Vosshall: I mean, really it’s just a crazy idea. Mosquitos are hungry for people. What if we feed them human diet drugs? Can we turn off that hunger? Can we trick them into feeling like they’ve already bitten us, that they already have filled up on our blood? We got all these human diet drugs, we fed them to mosquitos, they lost their appetite, we proved —
Strogatz: [LAUGHS] That’s so clever.
Vosshall: We proved — I mean, it’s crazy. So then we, we proved that the, that the effect was specific because we found, again, a receptor. This is a — this is like the target of that drug. We then use CRISPR to make mosquitos that lack that receptor, and all of a sudden, they were resistant to the drug, so the diet drug didn’t work on them. And then we looked for new molecules that, that wouldn’t be human diet drugs, but they would be mosquito diet drugs that would only work on mosquitos and ticks, and she found some molecules that, that are super specific for critters that spread disease, so ticks and mosquitos. And now we’re in the process of taking it to the next step, of coming up with more potent versions of those mosquito diet drugs, and the dream is to, uh, one day go out and just feed that stuff to every mosquito.
Strogatz: It’s an amazing idea. What about resistance, though, like bed nets? We didn’t talk yet about bed nets, right? You could put the mosquito nets over people’s beds, just a simple way to try to keep the — keep them out, keep them from biting and spreading malaria. Except that you, you mentioned that the mosquitos have found a way around even that.
Vosshall: Yeah, so the — I mean, bed nets are an amazing technology, and they’ve — they’ve saved a lot of lives, so there’s a clear impact of distributing and using insecticide-treated bed nets. But they’re, they’re treated with insecticides. Insecticides kill mosquitos, so all the mosquitos that are flying around trying to bite people at night die. That saves lives. All the mosquitos who are not flying around at night don’t die, and so then they slowly take over the population. And so then you have mosquitos that are flying around during the day when people are not underneath bed nets, and then you have a resurgence of these diseases. So this is just straight up Darwinian genetic selection.
Vosshall: So all the mosquitos that happen to have a slightly different work schedule — [LAUGHS]
Vosshall: — where they were hunting during the day, you know, weren’t… They, they were a tiny part of the population, and then they, they just end up taking over. So, so our diet drugs — you have to do the experiment. I mean, I don’t… The people who did the insecticide-treated bed nets, this was an unanticipated and, and unfortunate outcome. You only know after you do the experiment, but we think that the human diet drugs are much less likely to cause resistance because we are not using death as selection pressure.
Strogatz: Uh-huh. Okay.
Vosshall: So death is very — it’s the most potent selection pressure there is.
Strogatz: Sure is.
Vosshall: Everybody who’s susceptible dies.
Strogatz: Yeah. [LAUGHS]
Vosshall: And anybody who’s resistant takes over. So we are not killing the females that take the diet drug. We’re just taking away their appetite for a couple of days, and the appetite returns, and they — and those females, if they — if they don’t take another dose of our drug, will bite someone.
So, I mean, the overall effect that we would predict is every female that takes the drug, number one, won’t bite anybody for three days, and so then that has an immediate impact on the spread of disease, and that — that female who thinks that she’s taking a blood meal, who thinks that she’s satiated will not produce any eggs. And so you have probably a measurable effect on the total population.
Vosshall: But again, because we’re not using death, we’re using satiety and not death as selection pressure, we, we project that it wouldn’t have any issues with resistance, but it’s biology. I can’t — we’d have to do the experiment.
Strogatz: Right. I mean, ’cause I am a little puzzled about that explanation. I, I see the idea, but it does sound like still there’s adverse selection. They’re not going to have as many — well, either they, what, they — they won’t nourish their offspring as much or their — their eggs won’t be as well fed, so to speak? Or — it still seems like it’s harmful to them if they have been feeling satiated when they really shouldn’t be.
Vosshall: So if our drugs were perfect, if — if our drugs permanently turned off the appetite, and the female who took the drug never bit anybody, and therefore never got blood, and therefore never had children, you would potentially select for females who were resistant to our drug.
Vosshall: Now, the way to be resistant to the drug is to mutate the receptor that the drug acts on, and we know from our CRISPR mutant that mutating the receptor affects the fertility of the female. So they’re kind of damned if they do, damned if they don’t. If they have a functional receptor, they’ll lose their appetite. If, if you get resistance to the drug, those animals will be much less fertile. They’ll still be hungry for humans, but they’ll be much less fertile, and so you have — you’ll knock down the populations. But these things are really just… It’s, it’s like back of the cocktail napkin conjecture until you do it.
Strogatz: Is that — is that something you, you have in the works?
Vosshall: We are currently competing for funding to engage the services of medicinal chemists who will take our Compound 18 — Compound 18, very sexy name for our diet drug.
Strogatz: That’s a great name.
Vosshall: We’re going to make Compound 18+, so Compound 18, that is more… I mean, the dream is something that will have longer lasting effects so that females will take a longer break from hunting people.
Strogatz: You must get asked all the time, but I feel like I’d be remiss if I don’t ask you. Is this business about, um, some people being more attractive to mosquitos than other people?
Vosshall: That —
Strogatz: My, my friend… When I walk my dog out in the woods, my friend Linda, you know, insists that, that she’s attractive to mosquitos, and how come they’re not biting me? They’re biting her instead. [LAUGHS] So, it’s not — I assume it’s not something you’ve directly worked on, but maybe your work bears on this — this ancient question.
Vosshall: It’s an ancient question, and one of the most fascinating questions. And the case where everyone is a citizen scientist when it comes to mosquitos, because everybody notices it.
Vosshall: So we do study it, and it’s a real phenomenon, and… So there’s enormous differences between how attractive different people are to mosquitos. There’s two aspects to it, though. So if you ask people to self-report, to say, “how attractive are you to mosquitos?,” there’s actually zero correlation between their answer and the reality, and that’s —
Vosshall: And that’s for two reasons.
Strogatz: That’s funny.
Vosshall: One is that some people just get, get bigger reactions to the bites. So a bite will be much itchier and redder, and —
Vosshall: And so anybody that has that is just bothered a lot by it more — by mosquitos, and — and feels like they’re persecuted. The person next to them may be actually more attractive to mosquitos, but the bites are less itchy. That’s one part of it. And the other part of it is that when humans are… If a mosquito has a choice of a human or nothing, the mosquito will go after the human regardless. But if you’re in a grouping, as humans always are, mosquitos end up being choosy. So if you’re — if you’re the most attractive person at the picnic, you’ll get bitten. But if the next week you go to a picnic where there’s a more attractive person, you won’t get bitten, and so it’s all contingent on who else is at the picnic, and that’s why people self-reporting how attractive they are are usually wrong.
Strogatz: Uh-huh. [LAUGHS] So maybe it is the case that when my friend Linda complains to me, you know, maybe she is just the more attractive one.
Vosshall: She may — she may — yeah, she may — she may be more of a complainer, and the — and the bites might be itchier, or Linda may legitimately be more attractive than you are, to mosquitos.
Strogatz: Yeah. Yeah, yeah. I can take it. [LAUGHS]
Vosshall: And the only way to test it is to go into a laboratory and — and have us tell you who’s more attractive.
Vosshall: So we, we have to ask the mosquitos to tell us who’s more attractive.
Strogatz: Right. Right, right. So help us think like a mosquito just for a minute. What kind of cues are they using to, to find someone? What are they paying attention to, or what can they sense?
Vosshall: Yep. So the first thing that — if I didn’t make it explicit before, the — the most important thing to remember is that mosquitos bite us to get blood, and they need the blood to make eggs, and so from that statement, everybody will realize that only females bite. So males can’t bite us. They don’t want to bite us. They have no interest in us. It’s only the females that bite, and if they don’t get blood, they are sterile. They will not produce any offspring. So it’s the single most important thing that a female mosquito does, because it’s her fertility, and she needs the protein in the blood to actually mature the eggs.
And so for that reason — we think for that reason, because the evolutionary drive to get the blood is so incredibly do-or-die strong that females… They pay attention to everything. They love the way we look. They love high contrast. They love the way we smell, so they prefer the scent of human over every nonhuman animal that we’ve tested, including my dog.
Strogatz: Wow. Oh, that’s amazing.
Vosshall: They love our breath. So they love carbon dioxide, and they also love the heat that we give off. And then finally, when they get close to our skin, they love the humidity that we give off, and then also the taste of our skin. So — and all of these things they pay attention to, and even a partial — even a partial hint that there’s a human will get them attracted. So they — they really are — they are missiles. They’re sort of guided missiles that pay attention to everything that humans give off.
Strogatz: That is fascinating. It’s — I mean, you just think you’re standing there, you’re just sitting on a blanket at a picnic, minding your own business, and it turns out you’re — you know, you’re outgassing your [LAUGHS] your carbon dioxide, you’re sending out these heat signals, your smell. I assume it’s bacteria that’s smelling, that — that — when you talk about our human smell.
Vosshall: Correct, yep. It’s —
Strogatz: It’s not really us, right, it’s our bacteria that are along for the ride.
Vosshall: Well, it’s both. So the — yeah, the bacteria —
Strogatz: It’s both?
Vosshall: Yeah, the bacteria on the skin chew on the stuff on our skin, so it’s — it’s kind of the bacteria on the skin belching and farting out the, the scents, so —
Strogatz: Oh geez. You’re really some kind of guest here. [LAUGHTER]
Vosshall: But yeah, I mean, it’s like, it’s not — it’s not the mosquitos’ fault. We’re just — we are— you’re absolutely right. We’re just sitting there giving them all these “Come hither” cues. And I mean, people ask me all the time, “How can I avoid being bitten?” and the answers are kind of silly. “Go to a part of the world where there aren’t mosquitos. Stay indoors, or when you go outdoors, just cover yourself with DEET and wear a lot of clothes.” So it’s very difficult to avoid being bitten.
Strogatz: Coming up; why I end up outside my office in the math department with power tools on the Day of Atonement.
Vosshall: All right, can I talk about the one thing that’s really on my mind?
Strogatz: Yeah. Talk about what’s on your mind. I love that.
Strogatz: I had a feeling this was going to be good, because when someone says, “Can I tell you what’s really on my mind?”, you know that you’re going to get something that’s taboo, maybe, or dangerous, or maybe it’s something… You know, sometimes people will say, “Can I tell you what’s really on my mind?” and you’re about to get insulted. So I didn’t know where this was going.
Vosshall: Okay, what’s on my mind that I’m really burning up about this year is the dude wall. Do you know what a dude wall is?
Strogatz: I don’t know what that is.
Vosshall: A dude wall is… Every academic institution, every medical school, every college, every undergraduate campus, every graduate school, every institute has a dude wall. A dude wall is a display in a public area that has pictures of white men who are the former department chairs, or prize winners, or historic members of the department, often forgotten department chairs.
Strogatz: Yeah. Sure.
Vosshall: The department chair from 1920, and there — there’s usually a lot of them, it’s usually a lineup of between 10 and 50 of these pictures. And I’ve just recently been noticing that they’re everywhere, and that the people who walk by them are the very diverse undergraduate and graduate population that inhabits the conference rooms, and the seminar halls, and the lobbies. And so I’m on a bit of a mission to try to get the word out that if you have a dude wall, you should ask yourself what purpose is it serving, what messages is it sending as you have, you know, undergraduate population… They’re 50% female, and every institution does its best to bring in underrepresented minorities, so that the diversity of the… The mission of every educational institution is to educate, and the students do not reflect the demographics of the dude wall, so —
Strogatz: Mm-hmm. Mm.
Vosshall: So, so this is just something that I think a lot of people have forgotten. That they’re up, or they think that they reflect a history of the department, that they’re a lovely thing. I would never — no matter how prominent I might ever become, I would never sit for a portrait to have my portrait painted for a dude wall, or have a picture taken. I just think it’s a bizarre throwback, and I think it does actually affect the climate. We have to do everything we can to make the climate inclusive and welcoming to people. So if you — if every day you walk down the hall and you see all these old white dudes, it kind of says that it’s the old white dudes who get the acclaim, whose picture’s on the wall, and that we’re all just little expendable worker bees. So, we’re working on that at Rockefeller.
We have a huge dude wall, and we’re in the process of kind of redesigning it to reflect the fact that there are women and, and minorities who also have made major contributions. So that’s my — I’m burning up about the dude walls this year.
Strogatz: Mm-hmm. So the one remedy is to make it less of a dude wall by, by including some of the people who are working — the more diverse people working there today? But you could also just take down the whole thing, right? That’d be a different solution.
Vosshall: I mean, they’re… Every, every institution has to make its own decision, but every institution — everybody in every institution should go out in the hallway and ask, “Is there a dude wall?” and the answer is definitely going to be yes.
Vosshall: And I mean, you can take it down. You can take it down, put it in storage. At Rockefeller, the dude wall is wonderful. It’s all of our Nobel and Lasker Prize winners. However, there have been many unsung women and minority scientists who didn’t happen to win a Nobel and a Lasker, and so we are kind of reshuffling, redesigning it, and recognizing the discoveries, the prominent women in science who are at Rockefeller.
So I think that’s an option. The new president of Brigham and Women’s Hospital — there was the most massive dude wall known on earth was up there. All these incredibly enormous oil paintings. Very dusty, very old, and they covered the entire wall from the — from the floor to the ceiling. You couldn’t even squint to see the one on the top, and so the first president of Brigham and Women’s just said, “Let’s just take this thing down. Just take it down.” And I think what she ended up doing was redistributing them to, you know… I mean, I think like one dusty old portrait is fine. I think that there is a history to an institution. Like show me one, but don’t show me 50.
Vosshall: So I think her solution there was a really nice solution as a placeholder. Just paint the wall white, and then maybe come up with some other way to reflect the culture of the institution. It’s the medical students there. It’s the graduate students. It’s the discoveries. It’s the staff scientists.
Most of biology, and I would say in your discipline also, is a function of many people. It’s not a lone genius.
Strogatz: I — I can’t resist mentioning what’s been happening in my own department about this. So we have — it’s something from the ’60s. It’s called — it used to be called — I think it was called something like “Men of Mathematics.”
Vosshall: “Men of Mathematics” in an undergraduate teaching institution?
Strogatz: Well, so yeah, let me describe what it is. So it’s — it’s this — it’s a poster that occupies a whole wall. It goes — I don’t know, must be like maybe 20 feet long. It starts in the year 1000. It’s a timeline, and it has little sketches, pictures of, you know, Galileo and Weierstrass and Riemann and Gauss, and all these great —they’re all basically dead, white, European men. I’m really interested in history of math, and I have this right outside my office, and I’m the one who resurrected it from the storage bin or wherever. It was in the basement.
It was going to be thrown away, and I put it up. And my colleagues — we have several female professors in the department, and they and some of our graduate students pointed out to me that they hate that poster, and it pisses them off every time they walk by it. And I totally hear them, and it didn’t occur to me because of this problem that even people of good will can be idiots about stuff like this, and I think I was, and now there’s the question of what to do. Should we — we could just simply take it down.
Vosshall: I mean, I don’t know what the right answer is. You can’t — you can’t change history. I’m sure it’s a beautiful image, but I think you just have to keep in mind what is the mission of your — what’s the mission of your institution? Are you a museum or are you training the future bright minds in mathematics? If it’s the latter, I don’t think you should rub people’s noses in the fact that history did not include them.
Producer Ellen Horne: Yeah.
Strogatz: So —
Horne: So buckle in.
Strogatz: Buckle up. All right. Dude wall, here we come. Okay. [LAUGHS]
Strogatz: After talking to Leslie, I couldn’t stop thinking about my dude wall, or well, my version of a dude wall. It’s actually a poster. So on Yom Kippur, the Day of Atonement, my producer Ellen Horne hopped into my Subaru with me, and we planned to confront this dude wall head on. But still actually it felt a bit uncomfortable.
Strogatz: Okay. [LAUGHS]
Horne: Are you excited?
Strogatz: I’m excited. I’m a little nervous.
Horne: Why are you nervous? Are you afraid we’re going to get arrested?
Strogatz: I’m — I’m apprehensive. I’m not afraid of getting in trouble.
Horne: You’re not?
Strogatz: I’m afraid of having a confrontation about whether I’m doing the right thing, and I — and I don’t know, but I think I am, because I know that the poster hurts people right now, and that doesn’t seem worth it even though it’s educationally a valuable poster.
It presents a very one-sided view of the history of math, and it does it in an absolutely gorgeous design. So what do you do when something is an artistic masterpiece of a different era and its sensibility is not our sensibility today and — and it’s hurtful to some people today?
Strogatz: Personally, I still think this poster is gorgeous. It’s a marvel of design. You know that, um, the couple, the Eames? They designed the Eames Chair? Well, they’re actually a married couple, Charles and Ray Eames, and they were the graphic designers of this same poster that was hanging outside my office.
Strogatz: But, but little by little, some of my colleagues and grad students told me that it bugs them. One time, a student that I was working with named Kelsey, who was a graduate student that was a teaching assistant for a course I was doing.
Horne: A woman.
Strogatz: A woman. Yes, she’s a woman, and she’s now a professor.
Um, but at the time she was a graduate student, and we were teaching a course together that was very much geared toward helping — encouraging students who hated math or who didn’t see the point of math, who thought it was boring or oppressive in some way, who — you know, who had math anxiety. This course was a very diverse class in every way you could think of: gender, race… There were a lot of seniors who had to figure out a way to take math. [LAUGHS] You know, they thought they were done. They ended up in this course. So this is a glorious course to teach. I mean, a lot of my colleagues don’t want to teach it, but I love teaching it because it’s all upside. The students already hate the subject. You can’t ruin them.
Right? And the thing is that they all have a very distorted picture of what math is because of their education up till this point. They think of it as all these arbitrary rules and procedures, and you have to follow this or that algorithm, and it doesn’t make any sense to them. And so when I show them in this course — Kelsey, too.
I mean, we really taught it together. We would show them just how beautiful and artistic and creative and imaginative this is, and how it’s an expression of the human spirit, just like everything else that they care about.
Strogatz: Meanwhile, you know — so Kelsey and I are, are this force for good, we like to think, except then I’ve got this poster hanging outside my office. And every time she comes to my office, she’s confronted with the fact that nobody on the poster looks like her, and there’s this message that’s unspoken but is very plain that this is what mathematicians look like, and that’s what they’ve looked like for a thousand years, and they don’t look like you because they’re men. And so, you know, it’s hurtful to her, and, and especially now that we’re in the 21st Century, she doesn’t feel like this is the right message to be sending anymore, and I have to say I agree with her.
So we’ve just pulled up to my department, and it’s looking pretty quiet, although most of the parking spaces are taken. But I think we can pull in here because it’s after hours. And so we’re just going to park right here, and we’ll worry about getting a ticket later.
Strogatz: All right, so we’re here, and, uh, this is it. This is the moment. It’s time for this dude wall to come down. Time for some action. Here it is. Cornell Math Department, goodbye dude wall.
Producer Ellen Horne: All right, show me to your dude wall.
Strogatz: All right, let’s walk. And so as you can see, there’s not much action here in the math department after hours. There, are you seeing it? Check it out. Here it is. Twelve feet of pure manhood. [LAUGHS] Grey and black from the year 1000 to the year 1950.
Strogatz: Of course, turns out, taking it down is a breeze.
Producer Ellen Horne: Let’s see. [DRILLING SOUNDS] That was pretty easy.
Strogatz: That’s nice.
Producer Ellen Horne: Couple more.
Strogatz: All right. Just on the other side of this wall, from where the monument to the “Men of Mathematics” had hung, as it happens, that night there was a math class in action. So we pop our heads in to see what they thought of our act of righteous vandalism. There’re about like — something like 30 people in the room, maybe two are white men like me. So we asked this room what they thought about the poster.
Student: Is this a controversy with the —
Strogatz: There’s a little bit of a controversy about it. Tell us about it.
Instructor Elise McMahon: I know the controversy.
Strogatz: Come tell us about it.
McMahon: [LAUGHS] I’m teaching.
Student: What’s the controversy?
McMahon: That it says, “Men of Mathematics.”
Strogatz: Right, and that’s why we’re taking it down.
McMahon: I mean, I would love — I would love to see a, a poster with “People of Mathematics.”
McMahon: I think some of the most badass mathematicians are people who are not on the poster. You know, Ramanujan and Emmy Noether. Like they’re —
Strogatz: You didn’t notice Emmy Noether? She was the only woman on the whole poster.
McMahon: Oh, she was? She’s on the poster?
Horne: She’s on the poster. Do you want to see how —
Strogatz: So we bring this instructor — she’s a grad student, Elise McMahon — out into the hall to look at Emmy Noether, the only female mathematician on the poster, and Emmy Noether is described in the poster as fat, rough and loud.
Strogatz: Um, yeah. Does it say much about her math? Emmy Noether’s math was fantastic. It does say “Emmy’s early work on invariance gave no hint that she would become one of the creators of abstract axiomatic algebra. She developed the axiomatic theory of ideals, introducing the ascending chain condition, gave a unified theory of non-commutative algebras…” Sorry, I’m getting worked up. She was such a great mathematician. [LAUGHS]
McMahon: Apparently — I heard that she was the one who realized that the fundamental group was in fact a group.
McMahon: Mm-hmm. Yeah.
Strogatz: No, I mean, the algebra that you learn today in algebra classes is from her.
Strogatz: She had the modern vision.
Horne: What class are you teaching in there?
McMahon: Uh, it’s the Theoretical Calculus and Linear Algebra.
McMahon: So it’s for all the kids who are like gung-ho about math, which is fun. [LAUGHS]
Horne: Steve was saying he teaches the other end of that spectrum.
Strogatz: Yeah, I’ve taught the class for the kids that have — you know, don’t want to take math. We call it math explorations, and it helps turn a lot of them around. They start to see why we love it.
Strogatz: You know, that’s the goal is to really help them see what’s — what’s beautiful and fun about it.
Strogatz: One of the things we do in that class is have them write a final project about a 20th-century math — using our posters.
McMahon: Seen them around, yeah.
Strogatz: We tried to populate the department with these posters of 20th-century and 21st-century mathematicians, and a lot of them are people of color, women, all kinds of — and they’re, you know — they’re not on this poster, but they sure deserve to be.
Horne: Well, thank you for letting us hijack you. We’re — we’re making a podcast for Quanta Magazine.
Strogatz: I have to say, you know, this has been quite a learning experience. I do agree with what Leslie Vosshall taught me. The walls of educational institutions should look like the people inside them now, in the present, not just in the past. They should look like the people here now and into the future. They should really look like the future.
Strogatz: Next time on “The Joy of x”, we’ll travel through space time with an artist turned physicist, Robbert Dijkgraaf. “The Joy of x” is a podcast project of Quanta Magazine. We’re produced by Story Mechanics. Our producers are Dana Bialek and Camille Petersen. Our music is composed by Uri Weber and Charles Michelet. Ellen Horne is our executive producer.
From Quanta Magazine, our editorial advisors are Thomas Lin and John Rennie. Our sound engineers are Charles Michelet, and at the Cornell University broadcast studio, Glen Palmer and Bertrand Odom-Reed, though I know him as Bert. I’m Steve Strogatz. Thanks for listening.
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