The Science of Everything Podcast - Special Episode: Evolution and Genetics

Episode Date: December 10, 2022

In this special episode I discuss various topics in evolution and genetics with Art Woods of the Big Biology Podcast. We begin by analysing various ideas associated with the extended evolutionary synthesis, including plasticity, epigentics, and niche construction, discussing the extent to which these ideas are a challenge or merely an addition to the mainstream understanding of evolution. We then consider several common misconceptions about genetics, including the idea of DNA as a blueprint and genetic essentialism. We conclude with a discussion of some politically contentious aspects of genetics.   If you enjoyed the podcast please consider supporting the show by making a PayPal donation or becoming a Patreon supporter. https://www.patreon.com/jamesfodor https://www.paypal.me/ScienceofEverything

Hello, you're listening to a special episode of The Science of Everything podcast. I'm your host, James Fodor. Today we're going to be talking with the Big Biology podcast, and in particular, one of its co-hosts, Art Woods. And we're going to have a discussion about genetics and evolution, including a discussion about the extended evolutionary synthesis. So we'll be talking a bit about some ideas about building on modern synthesis of combining Darwinism with Medellian genetics and some ideas about how that needs to be extended by incorporating ideas like niche construction, epigenetics, and plasticity. Then we go into talking about some popular misconceptions of genetics and evolution and how those may play a role in public understanding of genetics, as well as various political and public policy debates.

This is a pre-recorded interview, and at the start of it, you'll hear myself and Art introducing ourselves in our podcast, and then we go on to talk about evolution. So I hope you find this interesting. This episode does assume a little bit of background knowledge about genetics, So if you are a bit rusty on that, you might want to check out episodes 34 and 35, DNA structure and function, parts 1 and 2, as a bit of background. But without further ado, let's start the interview. I'm the host of the Science of Everything podcast, and I've been doing my podcast for about, well, 12 years now. A long time.

Yeah, yeah, on and off a bit, but pretty consistent for most of that time. And I started my podcast because I've been interested in science a long time. I've studied a few different degrees and I'm currently doing a PhD in computational neuroscience. But I have an interest in many different scientific fields, and I found that there wasn't really a podcast that kind of fit the niche that I was interested in. So that's what got me into podcasting originally. How many episodes in are you guys? Are you? Yeah, about 130 something.

I have a few special episodes as well that I don't number, so something along those lines. And you do all the sort of post-processing and editing yourself? Is it like a one-man show? Yeah, entirely one-man show. Great. Sounds intimidating. Well, I'm the co-host of the big biology podcast along with Marty Martin. We started it up about five years ago.

The origin story is Marty invited me down to Tampa, Florida to give a talk at his University, University of South Florida. And at the bar later, over a couple of beers, we started kicking around this idea of making a podcast. And like all good ideas that stem from a couple of beers of the bar, this one actually took hold. and so we're now up to, I think, 92 or 93 episodes releasing every two weeks. We're definitely not a one-person show. We have a couple of great producers right now and then a team of interns that help out with social media and writing blurbs for the show and sort of helping us do some of the editing issues.

So, you know, it's definitely a team effort, and it's evolved over the years into a, you know, what feels like a pretty well-oiled machine, but it is a lot to produce episodes every two weeks, and we sometimes have gaps just because of, you know, interviews fall through or audio issues, that kind of thing. So you're doing computational neuroscience for your degree, so you can tell me more about that? What's the topic in that? Well, that itself is fairly broad, but I'm focusing on language and particularly semantics, so study of meaning. I'm trying to understand how humans represent word and sentence meaning in the brain. So I'm studying different computational models

of semantics that are used in machine learning and natural language processing and trying to compare those to human judgments of word meaning and sentence meaning and so forth as well as neuroimaging data, which I'm moving towards at the moment. So to try to see what the computers can tell us about the mind, I guess. Neat. And what's your research background? I'm what I would call an eco-physiologist, so I'm interested in physiology of organisms, primarily insects. But I study that in the context of sort of ecological and evolutionary processes, so I'm interested in how insects interface with their local environments, especially a lot of issues related to plant insect interactions and the experiences that insects have of climate on plant

surfaces. So we think of plants as sort of giant climate filters that are, you know, filtering the macro climate, which is what everybody is talking about, into these microspaces where the insects live. And those can be very different than the macro climate. But also just kind of broadly interested in evolutionary patterns among taxa. We've also worked significantly on homeostatic systems. So thinking about the physiology of homeostasis, physiology of body size, some stuff about global patterns in body size evolution. You can look at it as broad and exciting or diffuse and unfocused, and which one of those I choose depends on the week. I can understand that. That might be a good jumping off point, actually, to talk about one of

the topics that we had listed down, which is different conceptions of evolution, I guess. And I listened to a couple of episodes on your podcast about this sort of issue, about different ways of understanding evolution, the genes focused versus the organism-focused concept. And this is related to a concept, sometimes called the extended evolutionary synthesis. Do you want to introduce that sort of idea set a little bit? Sure. And talk about your interest in that. Yeah, that'd be great. So Marty and I both are organismal physiologists, so we're really interested in organisms and particularly animals and how they work in their environments. And we've had a lot of conversations with colleagues over the years and on the podcast about the

roles of genes and the sort of basic processes of evolution that that shape the way lineages evolve and that lead to the outcomes that we see in organisms. And there's a kind of interesting history and interesting conflict and divide in the biological community right now that centers around how to view the roles of genes appropriately in evolution. And I think, you know, the sort of standard view, and I think we're going to get to this later in the conversation about the public view of the roles of genes is it drives from this this thing that happened in the earlier part of the 20th century called the modern synthesis, which is basically the origins of our sort of modern view of evolution. And it involved bringing together ideas

about genes and alleles and how traits are inherited with sort of important statistical ideas about how allele frequencies can change in populations. And that led to this super powerful way of thinking about evolution and about microevolution that involves focusing on genes and focusing on the alleles that make up genes and asking what are the forces that cause those allele frequencies to change? This view kind of permeates still a lot of the way people think about evolution. If you take an evolution class in high school or in university, you would hear about Mendelian. in genetics, you would analyze punnet squares, you would talk about the links between particular allelels and the traits that they influence. And, you know, what Marty and I have been interested in is a set of ideas that have been argued for by a group of biologists that are interested in

sort of moving beyond and developing new conceptions of the way evolution occurs. And so there's this phrase you mentioned called the extended evolutionary synthesis. which has been, we talked about maybe for 15 or 20 years pretty seriously. And essentially what people have argued that are proponents of this extended evolutionary synthesis is that the sort of bare bones of the modern synthesis sort of no longer capture all of the interesting things that we know are happening that affect evolutionary trajectories of populations. And so that extended evolutionary synthesis attempts to sort of identify what are those important things and, you know, how can we change our worldview of evolution a bit to account for them?

And I should just add here that, you know, nobody is saying let's throw away the modern synthesis. You know, let's, let's, that the modern synthesis is wrong. It's more that we've discovered a broader set of things now that influence evolution and we need to account for those somehow. And the question is, you know, how much does our point of view and our theory need to change to account for that? That's really interesting.

I've done a bit of reading on some of these issues before. I'm not an expert in evolution, but it might be helpful to make sure to check my understanding of the issue. So let me try to explain it in the way that I understand it, and we'll see how far we get. Great, yeah. So according to the modern synthesis, the evolution is sort of primarily driven by natural selection

of different alleles. So an allele is effectively like a variation of a gene. And those alleles are produced mostly through spontaneous mutations. And then depending on the selective pressures in a given environment, some of those alleles may be detrimental and are selected out of the population. Some of those alleles are favorable for some particular trait. Those alleles are therefore selected for and become more common in a population over time leading to evolution. And that's kind of a view that's focused on allel frequencies and kind of individual genes and the effects of selective pressures driven by Darwinian processes of like natural selection. And so is that a fair characterization of sort of the modern synthesis view? Yeah, I'd say that's beautiful synthesis.

I would give you an A on that answer if you put it on the exam. Okay, so that's where we're at, say, I don't know, 20 years ago or something. And then the extended evolutionary synthesis, not that it's one thing, but, you know, that sort of comes along and people have additional ideas that they want to kind of add to that. So I guess one question would be, what are some of the additional ideas that people feel need to be added to this? And a second question would be, how important are these new ideas? How much do they change our conception of evolution? Is it a small change? Is it a large change? Yeah, that's a great question. So let me just maybe talk about two or three areas where there's been

significant progress in directions that sort of lead a little bit away from just a strict view of the modern synthesis. So one of those is about what is important about the units of inheritance. And in the modern synthesis, of course, that unit is the allele, the genes. And that's viewed as the sort prime unit of inheritance. What people realize is that there's lots of other things that offspring inherit from their parents. And that includes things like epigenetics, so biologists confusingly use epigenetics in sort of a narrow sense, which means like additional marks, chemical marks that are made on the DNA sequence that affect the ways in which those alleles are expressed. And those are much more fluid over time than are the actual sequence

information. So those marks can be modified during the course of an individual's lifetime. They can be reset or not when they're passed on to offspring. And then there's the broad sense in which people mean epigenetics, and that is just simply everything that's not the gene sequence itself that gets inherited. And that includes a lot of things like materials that are packed into the mom's egg or the maternal environment in which the offspring grows up. There can be what's called ecological inheritance, so that where the offspring ends up is not just some random place in the environment, but it's usually often a place that's been constructed by the parents in some way and had its ecology modified. And in a sense, you can think of the offspring inheriting that

ecological influence of the parents. So it's a sort of broader conception of what it is that's being inherited across generations, and that includes many things besides genes. So that's thing number one. Thing number two is a kind of big idea about the importance of plasticity in the phenotypes that organisms have. So plasticity, just a sort of loose definition of plasticity, is that for a given genotype, the phenotypes that it results in are altered by the environments in which it comes into contact with. So in other words, phenotypes are the outcome of both information in the genome. and information and experiences coming from the environment.

And those can lead to quite radically different phenotypes in organisms. And there's been this sort of emerging view of the profound importance of plasticity in potentially shaping the evolutionary process. This has been articulated by Mary Jane West Aberhardt in her book in the mid-2000s, people like David Fenig, who we interviewed on the show last season. And the basic idea is that plasticity can, in a sense, lead the evolutionary process. It's not just an outcome of natural selection filtering alleles in the environment, but rather it can take a sort of leading role in generating variation that then becomes

important to the way lineages evolve. And this can occur because... Let's say a lineage shows some kind of propensity, early propensity for plasticity. Well, that plasticity is variation on which selection can operate. And selection can then canelize or magnify the plasticity, so that in a sense it's plasticity leading the way by creating the variation that becomes important to the evolutionary process rather than mutation and alleles creating that variation. Does that make sense?

Yeah, so the plasticity aspect is one I found a bit more difficult to understand. So let me check if I've got it right. So the idea is when you talk about plasticity, you're talking about phenotypic plasticity. I am. Yeah, so variation of the like observable traits of an organism. And so the idea is that, and this is where I'm not quite sure I understand. So, I mean, the sort of modern way of thinking about it is that the phenotype, sorry, that the genotype determines the phenotype. So that effectively the set of alleles and the genes determines the observable traits of the organism. Obviously, there is an interaction with the environment. But I guess the focus is often on when there's a change, when there's evolution over time, that's due to changing allel frequencies. But what you're saying is that the range of phenotypes that is possible can vary over time dependent on the environment. And so the, you know,

organisms' interaction with the environment to fix that? Yes, and maybe we should make this concrete in a way. So how about an example from David Fenning's work? So he's worked in the American West quite a bit on spadefoot tadpoles. And these tadpoles often live in ephemeral bodies of water. They're growing up and they need to metamorphose before the water dries up. And, And he's discovered this really interesting form of plasticity in many populations of these tadpoles in which there's one of two morphs or morphs that sort of lie in this range between this. And that is an omnivore morph that eats detritus and has a fairly small head and a small, small jaws. and a carnivore morph that has a very large head and large jaws, and it eats mostly like fairy shrimp and other tadpoles.

They can even be cannibalistic. And what he's shown is that in many populations, the carnivore morph is induced by the tadpoles having very early experience with meat. So if they get other animals in their diet, then there's a kind of biochemical cascade that influences the way they develop and they develop a larger head and a bigger set of jaws and they become carnivores. So what's super cool is that the propensity to become carnivore morph varies among populations and it even varies among species.

So sometimes it's very easy for populations to become carnivores. Other times they barely exhibit the carnivore morph at all. And here's the kind of super neat evolutionary outcome. So there's an ancestral species to two of the focal species that Finnege and his lab group have really focused on. That ancestral species shows a kind of plasticity so that if the tadpoles get meat in their diets, they show a very broad range of phenotypes and response. So there's like plasticity, but it's almost like kind of random disorganized plasticity, if you will.

And what they think has happened is that evolution has, natural selection has kind of seized on that set of different plastic responses and refined it in different populations in different directions. And so there's these two descent. lineages, different species, in which one becomes a carnivore morph very easily and the other doesn't. And there's even situations where when they overlap, one of the species is almost exclusively a carnivore morph and the other is exclusively an omnivore morph, as if they've kind of undergone a, like a niche separation. and where the populations occur by themselves without competition from the other species, then they show a broader range of morphs and plasticity.

So the sort of broad view here is it looks like that natural selection is kind of seized on this plasticity. The plasticity set the parameters for what's possible, and then that's been shaped in different descendant lineage. Yeah, so I think what I'm not quite understanding is how that difference, from the classical description of, you know, if there's one allele that, I mean, it's probably more complicated than one allele, but if there's one allele that predetermines for carnivore and the other for omnivore and then one is selected over the other in different environments, is that not what's happening here?

It is. I mean, and so you've sort of hit on this fault line, and that's exactly what, you know, defenders of the modern synthesis would say is that, you know, at the root, there's still allelic variation that's underlying all of this. And, you know, that allelic variation is just being shaped by natural selection just as we've understood it. But somebody interested in the extended evolutionary synthesis would say, well, you know, there's something different going on here. It's this sort of preexisting plasticity is sort of creating these coordinated sets of complex traits that kind of co-vary together in important ways. And it's that that sort of complex co-variation.

of traits that is creating the variation that is then refined by natural selection. So is the key difference there the source of the variation? Because at least traditionally, the source of variation is random mutation. Well, I mean, you can look at it as random mutation is creating these alleles that allow plasticity to differ among populations. But there's this sort of equally important influence of environmental variation in general the variation on which natural selection then acts. So a related question is, I have heard evolution defined as changes in allure frequencies in populations over time.

And I'm just wondering how that connects with what you've been describing, because if I can give another example, and I don't know how much this relates to the tadpole example, but it just came to mind, if you look at, say, heights of humans in populations around the world, especially like maybe before there was as much jet travel. we know that that depends on both genetic factors and environmental factors, particularly early childhood nutrition and nutrition of the mother and so forth. So if we observed over time, say, different populations, some staying at a relatively shorter stature compared to others due to nutritional differences,

I mean, I wouldn't have said that that was evolution, at least by the sort of definition of changing allel frequencies, because the allel frequencies didn't necessarily change. They could just be expressed differently in combination with like different environmental factors. I don't know if that's, it seems like what you're talking about is a bit different to that. Maybe it's the time span as well. But how does, I guess the question is how do we kind of describe and differentiate the effects of sort of changes in allel frequencies versus the interaction of the environment? Or do we have to think about this distinction differently?

I guess I'm not totally sure what your question is. I think, I think what you described is, you know, a very common circumstance where there's lots of alleles of small effect that influence phenotypes. And so height is one of those things, right? There's probably hundreds or thousands of allelic variants that contribute in some small way, each of them, to variation in height. And, but that also, there's a very large component of sort of diet, you know, childhood nutrition. There's also a component of this thing we talked about earlier, epigenetics. So, you know, some populations, for example, that underwent severe starvation during World War I or World War II, the offspring of those people can be different heights than, you know,

populations that didn't starve during those times. And that reflects the sort of legacy of epigenetic changes to their genomes from, you know, 80 or 100 years ago. Yeah. So I guess the question is what here? So the question is, how do we understand the relationship between environment and genetic change? So if there's a change in phenotype, that could be driven by genetic change or environmental change or a combination of both. So how do we sort of describe that in evolutionary terms? Like if we're focused on evolution is change in allel frequencies, then it seems that, at least sort of naively, one way that I would describe that is simply to say that there could be different causes of changes in allure frequencies,

but fundamentally what we're describing as the evolution is just the change in the allel frequencies. Yeah, yeah, okay, right. So this is a really typical way of defining evolution, and this is something that I teach in my own basic introbiology course at University of Montana, and you essentially define evolution as anything that causes changes in allel frequencies. And that's a very kind of standard and modern synthesis way of defining evolution. And it's real. I mean, this is a really important, really important.

process. The question is whether that's sort of sufficient to capture the evolutionary process among different lineages. And, you know, those interested in the extended evolutionary synthesis would say, well, probably not because there's lots of other things about, you know, the influence of environments on phenotypes that are not captured simply by those changes in allele frequencies, even though that's a very powerful thing, right? I mean, it's powerful for many, many reasons, and it's really driven the field of evolutionary biology over the last 60 or 80 years. Yeah, so that's why I raised the question about the human heights example, because if I'm trying to explain variation in phenotype,

then clearly variation in allele frequencies isn't sufficient for that, because obviously environments have a big factor as well. But I could imagine one saying that, well, look, anything that affects the phenotype that's not allele frequency is just, that's not like evolution, or that's a different question. That's like a different field or something like that. But I guess maybe that's part of the issue is what sort of counts as, yeah, what the question is to something. Yeah.

Well, and maybe that might be a good segue to this third kind of big area that I think is interesting. So maybe let's transition to that. Sure. And that's this idea of, it's a kind of suite of ideas that revolve around niche construction and something that has recently come to be called agency in evolution. And so what is niche construction? it's the activities that organisms undertake to essentially construct the conditions in the environment that they experience. So here's an example of that from my own work.

I had a master's student a few years ago, Victoria Dalhoff, who worked on tent caterpillars. And tent caterpillars in Western North America, they build silk tents communally. So the siblings essentially spend some time every day weaving silk into a kind of platform. And the caterpillars all hang out on the platform. They spend a lot of time there. And that platform acts like a giant solar collector. And it heats up their environment to a temperature that's much higher than they would otherwise experience in the spring in Montana. So they're usually out early in the spring when it's quite cool.

And so they've effectively constructed a thermal niche for themselves that's much warmer than the ambient environment around them. And that in turn affects their physiology and likely has affected their evolutionary trajectory. So if we can sort of generalize that idea, it is that almost all organisms are affecting their local environments. And so the environment is not just something that's out there that's doing the filtering or the selecting of alleles. Rather, the environment is something that the organism, along with its genes and alleles and genome, has actively constructed, and that's what's interacting with the organism and determining its relative success compared to others. And let me just mention one other idea, which is, kind of related to this. It's something we've talked with the philosopher Dennis Walsh about

and a few others. And that's this idea of agency. And the idea is that organisms and even parts of organisms have agency in the sense that they can move through their environment and, you know, minimize risks and take advantage of opportunities. And that what they're doing when they when they do that, is encountering a highly selected subset of the potential environments. And so this is another way by which organisms or cells within organisms are essentially constructing the experience that they have of the environment. And these two ideas, they importantly turn on its head this idea of the environment as a filter, and they instead point to this idea that the environment that's experienced is often,

and constructed. Yes, I find the idea of niche construction quite interesting. Obviously, we see that in a very clear example with humans, because there was many things about our environment that we've changed dramatically over the past 100,000 years or so. The idea of agency in this context is a bit new to me, and I confess I find it a little more difficult to understand. So I understand the idea that animals are actively moving through and interacting with the environment, and so it's not like the environment is just sort of passively there. The environment as interacted with the animal is kind of shaped by their behavior. But I guess, I mean, maybe this comes back to what we were just saying before.

But is the behavior of the animal not just another phenotype that is determined in part by its alleles? So if we say that, so for example, we say that an animal engages in a certain behavior, which leads to some kind of selective pressure or whatever, that is a phenotype that would be ultimately reflected in some allele change, which then is selective. for in virtue of contributing to a certain behavior. I guess that's like the mon synthesis way of describing it. Is this just saying the same thing at different levels of like with different words? Or what do you think is the substantive difference there?

I guess I would say I think you're right that that's what, you know, somebody heavily invested in the modern to this would say. But I think that that doesn't quite acknowledge this strangeness of, you know, the organism and all of its genetic materials and its physiological systems, constructing the very thing that is the filter that's exerting natural selection on it. So people interested in the extended evolutionary synthesis would say that that's just a bizarre idea and it just breaks down this idea of, you know, random genetic mutation resulting in populations of alleles that are then filtered by some

external environment. And what this sort of newer idea acknowledges is that there is almost nothing, no such thing as the external environment that's not itself, partly an outcome of the thing, you know, the internal processes and the genetics on which that constructed environment is selecting. And that's just so hard to wrap your mind around, but it seems like potentially very important for the way lineages evolve. Yeah, I guess it adds a much more complexity to the process because you need to think about the effects of the organism on the environment and not just, you need to think about it the arrow sort of both ways, not just the effect of the environment, but the effects of the organism on the environment, which then affects back on the organism.

Yeah, exactly. And so we've talked about, I think, three broad classes of things. So you mentioned plasticity, epigenetic inheritance and agency niche construction. So these would be all different components of the extended evolutionary synthesis. So one thing that I find, well, maybe difficult or just a bit confusing, is that do you think that these ideas share something in common other than the fact that they're sort of in addition to the moncenses? Or is this just sort of different things that people have said should be added on? Or is there an underlying commonality?

How would you characterize that? That's a good question. Is there an underlying commonality? other than being defined in opposition to the modern synthesis. Yeah, in opposition. Yeah. Yeah, yeah. I mean, maybe not.

You know, I'd say this is a sort of broad suite of ideas that sort of challenge these boundaries of the modern synthesis. And I think it's a, you know, it's a real and ongoing and fruitful debate about whether there's enough of these things and they're a big enough deal to require some fundamental rethink of the way. the modern synthesis works or not. I was recently reading a paper from a few years ago by Kevin Lalonde, who's been a big proponent of the extended evolutionary synthesis. And he and co-authors made a good point that there's sort of an important aspect here of just modes of thought and conceptions of the way evolution occurs. And that it's important when, you know, big theories like the modern synthesis run into the kind of choppy waters in some

circumstances to really think about this. I mean, is it just a question of expanding the modern synthesis so it swallows these new ideas and becomes a more elaborate theory, which is done very successfully in many circumstances over the past

50 years or so? Or does it require a change in a point of view in some important way? And I myself am not going to take a super strong stand on this. I think we still don't know. But it's a fruitful time for thinking about these things. And I think there's going to be a lot of progress made, you know, both philosophically about what the modern synthesis means over the next 10 years.

And also in terms of, you know, people setting up their research programs to pursue particular pathways and abandoning other pathways based on these, points of view. Yes, it's interesting. In reading about this, I've encountered sort of different maybe tones or ways of expressing the relationship between the mon synthesis and the extended synthesis. One variant is sort of saying, look, the extended synthesis is building on and adding to our understanding by enhancing and adding on additional components to the modern synthesis. Whereas an alternative way presenting it is a bit more confrontational, which is sort of saying, actually the modern synthesis is in some deep sense, like wrong or deeply flawed, and it's going to be replaced by some variant of the extended synthesis.

And this actually reminds me of something that's, I mean, I guess it's happened multiple times in science, but one that comes to mind would be like Newtonian physics versus, say, relativistic physics, whereas even today, some people will say that, you know, Einstein showed that Newton was wrong and replaced Newtonian physics with relativistic physics, like special relativity and general relativity. Whereas other people, and I guess more myself as well, I prefer to say that, you know, Newton was sort of right within certain constraints. And what Einstein showed was he highlighted what those sort of limits are and then provided a more general theory, which extends beyond that.

So I don't know if that you think is a process that's going here as well with people sort of describing the extent of the change or disagreement in different ways. I mean, I do. I'd say the other thing here is that I think this disagreement is kind of like a roar shock test for biologists. And it reflects like, you know, the relative sort of collaborative. approach versus confrontational or, you know, vitriolic approach reflects something about the personalities of the people that are involved. I mean, you know, I think for some people,

they're just sort of naturally, you know, they want to find a compromise and a sort of synthesis that puts all these things together. Other people are more willing to say, you know, look, these are major flaws of the modern synthesis. We have to throw the whole thing out and start over from scratch. I mean, I mean, almost nobody says exactly that. But I think those are the poles of the extremes. Yeah, and I think that's, the latter thing, I don't think I've seen anyone say that explicitly, but sometimes it's more like, it sounds like they're saying that, even if they don't literally say that kind of thing to, and that can be just a, I don't know, a way of

drawing attention to things or highlight the importance of their own work. Yeah, I agree. For listeners, there's a really interesting back and forth about this in, it's either nature or science in like 2014 or 15, and there's this sort of essays. for and against the extended evolutionary synthesis by major proponents for and against. And it's just a really nice sort of, you know, a couple of essays to read side by side. Maybe this is a good juncture to talk about one of the other issues that we had sort of on the loose agenda, which was the public understanding and misunderstandings of genetics.

And I guess we've been talking about how geneticists themselves don't always agree on things. But there are things that they do agree on and that, where they do sort of differ from. from the public. So I guess maybe is there any, I mean, in your sort of work both as a researcher and also as a podcaster, or just as a general concerned citizen or in whatever other context, are there any particular understandings or misunderstandings about genetics or public genetic knowledge or evolution as well that have been important to you or that you've noticed or you think are particularly salient? I mean, yeah, you know, I think the phrase that you hear the most often from the public and the one that's the most jarring to, to myself.

and I think to most working biologists is this idea of genes as blueprints, right? I mean, you hear that metaphor all the time. And it encapsulates, I think, so much of what's wrong about our understanding of how genotypes map on to phenotypes, right? It sort of implies that there's this plan, and you have this plan in your genome,

and that plan is going to be executed by your cells and your organ systems. And that's going to result in all the phenotypes that we see. And, you know, I mean, if we just think about that metaphor for a second, genes as blueprints, like what really is a blueprint, right? A blueprint is a drawn plan for a building, let's say a house. And superficially, that contains information in the same way that the genome contains information. And maybe let's be explicit about that.

So a blueprint is like a two-dimensional drawing that is meant to represent a three-dimensional thing, which is going to be built, right? And in another way, the genome and the genes it contains are like one-dimensional information, right? It's strings of letters. And those specify a thing, in a sense, that's going to be built. So very superficially, they appear to resemble one another. And so it's a sort of easy shorthand to call genes, blueprints. But that's really where the similarities end. And here's a couple of issues.

So you can think of blueprints for a house as being like a 2D to a 3D mapping. Genes and genomes are sort of very loosely like a 1D set of information that's mapped onto, let's say, a 4D organism, right? So it's a 3D organism in space that's persisting through time, which is another axis. And phenotypes are changing all the time during the course of an organism's lifetime. And maybe the biggest thing is a lot of these issues we've already talked about, that the genes don't just specify the phenotypes. There's this complicated dance with all of the environmental influences that occur. during development and during an organism's lifetime.

And that just fundamentally doesn't happen with blueprints for a house, right? I mean, it's actually kind of interesting to think of like, what if they did, right? So like what if, you know, what a blueprints really were sort of like exhibited plasticity? So if we built the same blueprint house in Missoula, Montana, where I live, and I send it to you and you built it in Melbourne there, those environments are very different. and so that same two-dimensional drawing should give very different houses in the end.

And that's, of course, not how blueprints actually work. I think that's the thing that maybe disturbs me the most about public understanding of genes. Yeah, the thing that I would say is the biggest misunderstanding. Maybe it's hard to quantify that. But I think it relates to what you're saying is the idea that I think a lot of people don't really understand what a gene is. And the way that I like to describe that is by saying that genes code for protein, not for behaviours or characteristics. So there are some specific genes that correspond in a direct way to a particular observable

characteristics, but those are definitely in the minority. And, I mean, it's even more complicated. It's not like one gene codes for one protein, but at least at a simple level, we can say that there's like 30,000 genes that they code for 30,000 proteins. But those different proteins are doing so many different things and interacting in a very complicated set of metabolic processes. we should not really think as if having a particular variation of a gene which translates in any particular way to any characteristic that we could observe or relate to.

And that's different to like a blueprint where you'd say, oh, look, here's this part which specifies the size of this wall, what it's going to be made of, how many stories this has, like the width of the window, stuff like that. There's a direct correspondence between aspects of the blueprint and things that you can observe and that are sort of macroscopic and makes sense. Whereas in genetics, that's actually rare, as we've been increasingly. recently finding, it's often very hard to make any sense of what the genetic information is

sort of actually corresponding to at a level of the phenotype. Yeah, yeah. I mean, it does happen, right? I mean, there are alleles that have a very direct correspondence to phenypic effects, yeah. It does happen sometimes, but for the most part, it's very complicated. And the other thing is that many of the, many genes code for transcription factors and other types of proteins, which are basically specify how other genes, some look for expressed. So that would, I don't even know what the analogy for a blueprint would be.

be like if the instructions of the blueprint didn't actually specify anything about the house, but just said things about other parts of the blueprint. And you could imagine trying to build a house on the basis of that, I think it would be rather different. It's an interesting exercise. So if there's any engineers out there listening, we need sort of, yeah, let's reverse the analogy so that blueprints for houses are arranged like information in a genome. Yeah, and I think that this relates to something else as well, which I think some people have called genetic essentialism, which I think is quite interesting. And I think that this is propagated to an extent by Hollywood, maybe, as well, which is the idea that a person's like essence or fundamental

nature is determined by their genetic code. And I don't know that people necessarily consciously think this, but I think that it's an idea that people sort of have where it's like, oh, well, if you have the same genes, then that specifies like who you are, which, I mean, that's not even really true for like a house made from a blueprint, right? Because you could build two houses from the blueprint and they could be slightly different. But I mean, obviously for biological organisms, the difference is even more stark. We're shaped by our environment and our experiences to an enormous extent. And all of that is not pre-specified in the genome. But yeah, I don't know exactly why that sort of language and way of thinking persists, but I do see to encounter that.

Is that something that you encounter as well? That sort of... Yeah, yeah. No, I think there's a lot of genetic determinism and, you know, it comes out in a lot ways. I mean, you know, the sort of iconic movie about this is Gattaca, right? So, yeah, yeah. You know, people's prospects for the future and their employment opportunities and the, you know, the things they can do in life are determined by what the government finds in their genomic sequences. You know, I would say, I think this genetic determinism is, is allied or maybe a symptom of this idea of viewing genes as blueprints. And, you know, it totally under, undervalues the huge role that environments play in determining phenotypes.

I would say I wanted to return to one idea that you brought up just a few minutes ago, and that's, you know, how should we think, and how would I like the public to think about genes and genotypes? And I would say, you know, for me, one really useful way to think about genes and genomes is like a super important library of information. It's an organ that organisms and cells can use and draw on. And they're all the time checking out the individual books from that library and making use of them and then putting them away. So it's not like, you know, some blueprint that has executive function that's controlling

all of the things about you. It's more a repository of super vital information that your cells and your body are drawing on when needed, but in circumstances that reflect this kind of complex mix of all of your environmental influences and your current physiological state and all of those things. Yeah, it's a bit more like you use a manual than a blueprint. I don't know, that's not a very good analogy either, but it's it's something that you can, yeah, because basically the genes are expressed in certain contexts, right, when the right environmental stimuli are present and when there's the right interaction of other genes.

And so it's not as sort of linear as a blueprint where it's just, well, I suppose there are some very basic genes that are nearly always expressed. But for the most part, there's a great deal of variation. And so thinking about it in terms of, well, here's the blueprint and then that's just sort of exemplified in the real world. It's not very helpful. And I would say here's one of the thought about, you know, where some of this misperception comes from. And I think, honestly, it comes in part from the way we teach evolution. in schools. And I don't know how it's taught in Australia, but at least in the U.S., there's a lot of focus on Mendelian genetics. And even I am guilty of this in my intro bio course at the University

of Montana talking a lot about Mendelian genetics, which of course are like super important. Everybody has to know about Mendelian genetics. But without sort of additional discussion, it kind of gives the sense that, oh, yeah, if you know the alleles, then you know. know the trait of the peas, right? They're green or yellow. They're wrinkled or smooth. Individual alleles are determining those things. And even in Mendel's case, that's a little more ambiguous than his data had suggested. But I think there's almost like a kind of built-in assumption here that all traits are like this. And I think we as educators maybe don't do a good enough job of talking about that as a starting point and then going on to these much more complicated ideas

about polygenic traits and plasticity and all the other things that I went on about earlier in the show. Yes, that was my exposure to genetics in high school was Mendelian genetics. I didn't do biology in like the year of 11 and 12, the top TV. So I guess there would be more coverage there. But yeah, I think that that, I think they usually, you know, usually there is some sort of gesture to the idea that the environment is important as well. but the natural focus of trying to teach teenagers about genetics is to get the punnet square and understand how that works, right?

And I think that in that case, it does emphasize the direct connection between allele and the corresponding phenotype. But even in cases, like, simple traits of pea plants, I mean, if you plant the pea plan in the middle of the Sahara Desert and don't give it water, I mean, it's not going to, it's not going to show that phenotype. You're not going to have yellow or green seed pods. Yeah, exactly. So I think that, yeah, that part of the issue there is when you sufficiently control the environment, then what the variation that you will observe will largely be due to genetic variation.

But that in itself is sort of an artifact of the fact that you've controlled the environment. And actually, that's a common, this sort of a parenthesis, but that's a common issue in studies of heredity in humans, which, I mean, I guess that's a whole other podcast discussion. But I am very critical of how that, not so much how the research is done, although there's some issues there, but largely how it's communicated. about what hereditary even means and about how you sort of, how you parcel out the effects of genes and environment there. And I think that there's a lot of misunderstandings of that. But anyway, yeah, yeah, how would we, here's a question, how would we teach genetics at a high school level if you had your druthers and we, you could write up a new curriculum? What would it look like? Oh, that's a good, broad question. Well, if it's not mental, I mean, it's got to be something else.

Well, no, I think we need to start with Mendel because that sort of communicates in a very powerful way the sort of basics of inheritance, which are critical. But I think very rapidly we need to move on to much more complex traits and talk about where does variation come from. And that's drawing on complicated pathways from variation in alleles to variation in phenotypes, but also much, much more emphasis. on the role of environmental variation interacting with genetic variation and other kinds of inherited information to influence phenotypes. I almost said to determine phenotypes, but I think we need to move away from this verb, determine even. I think it's not a useful way to think about it. And so that just involves a more nuanced and complicated view of biological variation where it comes from. And that takes more time. And it takes sort of a more

sophisticated understanding on the part of the instructors. And, you know, so I guess that's going to be a hard thing to implement. If I can be supposed to answer my own question, although my answer is a little bit different. So my, your focus is sort of organismal biology. Now, I study neuroscience at the moment. In the past, I did several years working as a research assistant at a structural biology lab, and we study proteins. So I guess my bias is on the sort of protein level of study. And it often kind of frustrates me when if you talk about genes or genetics, people have at least some idea of what you're talking about. But if you talk about proteins, like also you study nutrition. Like, no, no, no, no. But most people don't know what proteins are other than a like a macro

nutrient. And I think that's really problematic because genes code for proteins, right? So I think that we need to emphasize the relationship between those two a lot better. And I think that that's not going to, that's not going to be sufficient, but it will help for people to understand what genes actually do. They don't just code for like phenotype straight up. They code for proteins and then you have to ask the further question as to, well, what are those proteins do and how do they interact with metabolic networks and so forth? So that would be my suggested alteration there. And I don't, I agree. I don't recall learning anything about proteins when I was in high school. So whereas I did learn about genes. So I think that that's kind of a problem.

I think I did learn about proteins, but maybe just they were described as enzymes. Right. So they catalyzed reactions. But somehow I didn't get that there's, you know, multiple levels between genes and phenotypes. And, you know, proteins is one level. It's also RNAs in there. Don't forget about RNAs. But then also sort of all of the physiological systems and homeostatic systems and organ systems

that have lots of kind of feedback and feed forward loops. That's like another level of complication in there that is, in a sense, you know, detaching allelic variation from phenotypic variation via these sort of constructed pathways that the organisms make and that are usually exquisitely sensitive

to nutritional and environmental influences. I was going to say, let me ask you a question, which is what's your perception of Australian versus American conceptions of these issues, genetic determinism and genes as blueprints? And I don't know if you've spent enough time in the U.S. to have a sense of that. Not really, although we get a lot of U.S. media here, but I don't know that there's a major difference, especially because there's so much overlap in sort of popular media and even political issues. One thing that I do know is different

is that creationism and explicit opposition to evolution is much bigger in the US than it is in Australia. It does exist here, but it's not nearly a significant, and certainly it's not a politically relevant force. Maybe in parts of Northern Queensland, it is a little bit, but that's the only difference that comes to mind. I think that broadly speaking, things like genetic essentialism and determinism and other things that we've discussed, the genes as blueprints, it's fairly similar. I don't know if that differs in like Asian countries or in Europe elsewhere. Maybe our listeners will have some better sense of that than I. Yeah, I've spent quite a bit of time in different parts of the world, but I, you know, I don't, I guess I don't really know what the public thinks in many of

those places, because usually if I'm somewhere else, I'm in a biological bubble talking to biological colleagues and we have sort of a common set of assumptions and, you know, knowledge about this stuff. Yeah, well, that can be a blessing and a curse, I suppose. Maybe that is a good way to segue to the sort of last question area, which we kind of already talked about, but I sort of had as genetics in society and policy and politics. I guess this is a bit amorphous because there's just genetics itself is not necessarily politicized, but it becomes relevant in different in discussions.

I remember this was like 15 years ago. People were talking in the media about the idea of a gay gene and the relationship with like gay marriage and things like that, which is a bit of an old-fashioned thing to talk about these days. But I do recall that when I was late high school. So I guess there's lots of other issues that come up now. But I just wondered if you had any sort of general reflections on genetics knowledge and society and policy more generally

or any relevant issues that might come to mind. The thing I'm thinking of as you talk about that is, you know, the current focus on trying to use genetic information to make informed decisions about medical issues, right? Yeah, that's probably the most salient one at the moment. You know, this sort of multiple things going on here, right? One is that we know that some diseases have a genetic basis in the sense that having particular alleles or particular functional or non-functional versions of a given. in gene affect your propensity to get a disease. And we've known that for a long time. I would say the sort of new frontier here comes from the fact of being able to do genome-wide scans now. And there's sort of different ways that that can happen, right? So you can now, many companies

will assess thousands of what are called SNIP, single nucleotide polymorphisms. So they're very variable spots across the genome that may or may not be inside of particular genes, but are linked to them and therefore statistically associated with them. Often we don't even know what those genes are, but you can construct statistical models that tell you about how variation in those snips relate to different traits, and those can include disease traits. they can include other kind of non-disease phenotypes. So like a few years ago, I did the 23 and Me ancestry thing

where I, you know, spin in a tube and send it off to them and they did this SNIP analysis. And they sent this interesting analysis back that focused on, you know, my probable ancestry. But also they tried to predict different traits that I had. Like, you know, do I have hair on my back? That was the one that somehow caught my attention. I don't remember the others, but there was a whole suite of traits.

You think there'd be easier ways to answer that question than getting your gene sequenced. I know, I don't. Like, look in the mirror. I mean, and then there was, you know, like medical information as well. And then the sort of even finer resolution approach to this is to sequence people's entire genomes, and that's going to increasingly happen. And that gives you even more information than just the SNPs. But, you know, this is getting it.

used in interesting ways. We had on the show last year an interesting conversation with, on Big Biology, a conversation with Catherine Page Harden, who maybe you've heard of. She wrote a interesting and kind of controversial book, I think last year or the year before, called The Genetic Lottery. It's about using what's called this technique called G-WAS, which genome-wide association studies, which essentially is taking information about a genetic lottery. a bunch of snips across the genome and collapsing it into a kind of numerical score that's

associated with different traits that someone might have. And she's a big advocate for using that information in studies of human traits and other sorts of kind of sociological traits. So how do you design the best sort of educational system? or how do you do psychological interventions? And she's an advocate of using these G-WAS scores as a way to inform those studies to make them more powerful. That's been like an incredibly controversial idea

because she goes, she's very careful not to go down this path. And in fact, she actively writes about her uncomfortableness with it. But it's in a sense, you know, reducing somebody to a sort, score and then talking about the influence of that score on their phenotype. And it's not exactly genetic determinism because you're not saying that score causes the phenotype, but it's sort of linking genetic variation in a very abstract and statistical sense to variation in phenotype and human phenotypes. And I think that feels to a lot of people like a very dangerous path to given the use and misuse of genetic information in the past?

Yeah, so I did listen to that episode, actually, and it was quite interesting. I think, well, maybe I'm just forgetting, but I don't recall getting a clear sense of, from listening to that, exactly nature of why her results are considered controversial in some spheres. Let me see if I can explain in how I understand it,

what she is advocating in doing. So if we're testing, say, an educational intervention, and in doing so, we run some kind of, statistical analysis of the different factors that affect educational and educational attainment, because I think she focused on years of schooling as one example of something that we want to measure in a social context. One thing we could include is this genome-wide genetic score, which is a way of controlling for genetic variation, like in different populations, which can then give us more power, like statistically speaking, to identify the effects of

our intervention. Is that the essential idea that she's driving at? That is, yeah. That's a great summary of. of what she's advocating. And I would say, you know, I'm on the fence about that. And what the critics would say is that, you know, in a sense, we don't need genetic information to know already what to do, to do successful educational interventions. Like, we know a lot about what creates good learning environments

and raises test scores and what does the opposite. I think Catherine Pageharden may disagree with that a little bit. And the critics would also say, you know, there's a real sort of danger here in starting to implement and use genetic information like that because, you know, what if kids very early on their information is known, and they're somehow tracked into different tracks based on their G-WAS school? Catherine Page Hardin is not advocating that at all, and she writes passionately against that idea.

But I think there's a danger in, you know, associating genetic scores with individuals. in ways that may affect their opportunities. Yeah, it's interesting. I guess that that's a long discussion. One observation that I would make is that potentially, I mean, this doesn't address all aspects of why that could be an issue, but I think that part of it could be the way people would interpret such a score or may interpret such a score,

which links back to what we're saying before about public understandings of genetics. If people think that something like intelligence or educational attainment is strongly genetically determined, then any sort of tracking of a score based on genetic factors could be interpreted as some kind of like ultimate prediction or limitation of someone's capability or something like that. And partly that could reflect just a misunderstanding about that. So perhaps part of, perhaps in a society where genetic information is going to become, well, already is and will continue to become more widespread and there'll be questions about its use. It's increasingly important for people to have a better understanding about what that information is. does it and does not tell us and what it means.

I agree with that. And I would say, I think you nailed it too by pointing out that the danger stems partly from this sort of public idea of genetic essentialism. Yeah, yeah. So I think, you know, the biologists, we could talk about this, and we could agree that there's no causal relationship and there's lots of, you know, complicating factors, and there's no straight line from GWAS score to phenotype. But, you know, will the public understand that?

and will administrators who are not biologists understand that? I think there's a lot of danger there. Yeah, I think there are probably other cases as well where this sort of genetic tools will become increasingly, well, there'll be calls to apply them in different contexts. And I think that that's one of the reasons why to draw things back to a broader level. Public understanding of science is important

because even if you're not a scientist or work in a scientific field, we're called upon to act on the basis of scientific information directly and indirectly, like essentially all the time. Yeah, yeah, yeah. I have an idea. I think the public should listen to more podcasts. I mean, clearly, that's not. Yeah, yeah.

That couldn't, yeah. I mean, pick some good science podcasts. I think that couldn't. Yeah, exactly. Anyway, you had one last question. Oh, no, my question was just if there are any last questions or comments that you wanted to make, anything else that you wanted to touch on. I don't think so, but this has been super fun.

I really enjoyed the conversation, and I think we covered a lot of ground. Yeah, it was good. It was good. And I learned some things about the extended evolutionary synthesis will be good. I'll have to cover that in a podcast episode sometime. I don't know if I totally clarify it or not. It was helpful. I need to read more about the plasticity side of things. I still don't fully get that, but it's certainly very interesting. Yeah, well, it was a pleasure to chat. Yeah, same. So that concludes the interview. Hopefully you found that discussion interesting. Again, this is a special episode, so the next recording will be returning to our usual format. If you're interested in checking out more from the Big Biology podcast, feel free to look them up and check out some of their other episodes. They have some quite interesting material, so I recommend them. If any of you would like to support my podcast, you can do so by leaving a like on the Facebook page.

You can leave a review on any of the aggregators of your choice, or you can support financially by making a one-off donation through PayPal or becoming a Patreon supporter. I very much appreciate all of my backers or people who review the show and leave feedback. that is much appreciated. If you'd like to get in touch with me with any questions, suggestions or other feedback, feel free to send me an email. My address is FODs12 at gmail.com. That's FODDS12 at gmail.com.

Thanks very much for listening, and I'll talk to you again next time.