Greg Radick: Disputed inheritance - Raphael Weldon, William Bateson and the battle for genetics
Image courtesy of Prof Greg Radick
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In Weldon’s opinion, Mendelian genetics simply didn’t work to explain the complexity of inheritance and the wide distribution of traits in real life organisms. But just as the argument got going and Weldon and his acolytes started to gain the upper hand over Bateson’s ‘unstatistical’ view in the debate, there was an unexpected twist…
This controversy is described in exquisite detail by Professor Greg Radick from the University of Leeds in his new book Disputed Inheritance: The Battle over Mendel and the Future of Biology. I sat down for a fascinating chat with Greg to delve into the history of the war of ideas (and words) between Weldon and Bateson, and its knock-on impact on the way we’ve thought about and taught the science of heredity all the way through the 20th century to today. But we start the story not with Bateson and Weldon, but with another somewhat infamous man, who you’ve also heard me talk about before on this podcast.
Greg: By 1900, the figure who had emerged as the most exciting commentator and theorist on inheritance was a cousin of Charles Darwin's, named Francis Galton. Galton was younger than Darwin and worshipped his relative, even more so after The Origin of Species came out. And Galton writes a fan letter to Darwin, in which he says, you know, "Your book has just liberated me intellectually. I feel as if I had been a savage, lumbered with these mythic ideas, but I've now seen the truth."
Greg: And he changes his ambitions between that time and the next few years, away from geography, which is where he made his name as an African explorer, and towards inheritance. And in that same year, 1865, the year of Darwin's Pangenesis manuscript, the year of Mendel's lectures, Galton publishes a couple of articles in a magazine called Macmillan's Magazine, called 'Hereditary Talent and Character' in which he set out to show, making use of data that he'd collected by ransacking biographical dictionaries, that eminence, the ability to rise in society, was hereditary - that if you have an eminent relative, you are much more likely to be eminent yourself, and likewise to have eminent kids than someone who isn't related to anyone along those lines.
Greg: And so he shows empirically - to his satisfaction at least - that this is the case, but he also explains why this is important. And he thinks it's important because civilisation is in trouble. Civilisation has become immensely complex, and we need leaders who are up to the job. And plainly, Galton says, our current leaders are not. So how do we get our best leaders up to par? We breed them into being.
Greg: And a major part of Darwin's case in The Origin of Species for the theory of natural selection is the power of breeders on farms to use selection in order to breed new and improved varieties of pigs and cows and horses. Well, Galton says, "Imagine if we gave anything like that level of attention to our own breeding, what we could be like," as he says. "The galaxy of genius that could be created, if even a fraction of the selective attention we give to our domesticated animals and plants we gave to ourselves."
Greg: That's where this is going. So in 1883, Galton gives that project of improving the human stock through scientifically managed breeding its enduring name: eugenics. But the project is there right from the start and it's explicitly the motivation for getting serious scientifically about inheritance: we need to understand this because we need to improve ourselves or we're going to be in big trouble socially.
Kat: Okay, so we've got a few strands that I want to try and weave together. So we've got the Galton strand and his work and a lot of what he's doing to understand populations, measure them, doing all these statistics that in some hands will then, you know, turn into very bad stuff in the form of eugenics.
Kat: But then there are these other strands of these people which are Bateson and Weldon. So where does this strand start? Let's start weaving this one into the story.
W. F. R. Weldon
Greg: With the likes of Charles Darwin and Francis Galton, we're still in the world of the 'Victorian gentleman of science'. Right so both Darwin and Galton are independently wealthy, you know, they don't have to produce papers, they're not part of what we recognise as the 'professional' world of science that's familiar to us.
Greg: By contrast, in the next generation, there come along really the first generation of people who recognisably belong to 'professional science' in the ways that we recognise it. And people who go on from there to be ambitious about publishing in the top journals, in having students who carry on their research programmes.
Greg: And so in the latter part of section one of the book, I introduce the readers to W. F. R. Weldon and William Bateson, in the first instance as friends who met when they were studying zoology at Cambridge in the early 1880s, and who are part of this first generation of 'professionals' in biology. And they are people whose ambitions are entirely formed by the rise of Darwinian evolution as reshaping biological knowledge, and they see themselves as devoted to the big research enterprise at the time, which was reconstructing the tree of life on the basis of animal form - or morphology, to give it its fancy name.
Greg: But they were also part of an advanced discussion there at Cambridge about natural selection. And in the programme of reconstructing the tree of life, natural selection is kind of a problem, right? Because how do you reconstruct the genealogy of the animals you're interested in? In part, it's by looking at animals that are similar and trying to work out when similarities across apparently related animal species point back to a common ancestor. But you're also aware that because of natural selection, sometimes animals can end up looking similar, not because they've inherited common features from some ancestor, but because they've converged adaptively through natural selection to look similarly as adaptive ways of coping with similar environments.
Greg: So natural selection is kind of a problem for the whole research programme that young Weldon and young Bateson are signed up to. And they respond to that in different ways. In Weldon's case, there's a search for some way of turning what is a problem for this older research programme into a new research programme: how do you operationalise research on natural selection? And Weldon finds the answer he's looking for in a book of Francis Galton's. In 1889, Galton publishes a book called Natural Inheritance, which kind of brings to a climax and extends the work that he'd been doing now for decades on this subject. And this book blew the minds of the most ambitious biologists, anthropologists around the world, because it showed how statistics could enable one to be quantitative in the ways that were always impressive in the sciences, about evolutionary questions and about questions on inheritance.
Greg: And Weldon grabbed this with both hands. And throughout the 1890s, he developed a new reputation - and a really important one, right, this is how he gets into the Royal Society - by showing that the statistical work that Galton had pioneered using data from humans collected at fairs and things like that, that those same techniques could be applied in the wild, in studying, for example, shore crabs in Plymouth Bay. And through extending the work that Galton had done and enriching it with experimental work, Weldon was able to show natural selection in action in Plymouth Bay, which was increasingly becoming polluted, and to show that if you measured precisely lots of individual organisms, year on year on year, you could detect change which was otherwise going to be invisible. And you could explain that change as adaptive, right that as conditions changed, there was selective destruction of the organisms that happened to be born in ways that led them to grow up to be less optimally adapted than other organisms.
Greg: So that's what Weldon took out of Galton's work. Bateson, by contrast, ended up rejecting the Darwinian emphases on gradual evolution and the adaptation of organisms to environments. He ended up convinced that all of that was actually pretty secondary in evolutionary change. What really mattered were the internal dynamics within a species. So that what we should expect is not gradual evolution as environments change and organisms change along with it, instead we should expect to find that organisms are stable for long periods and then suddenly there's a leap - a 'saltation' in the technical word. And these leaps are not random, they're to points of stability, which are themselves kind of pre-programmed within the organism's structure.
Greg: And Francis Galton, rather fascinatingly, in that book, Natural Inheritance, supports both of these programmes. One of the surprises, I hope, for readers of the book, is that Galton, who can sometimes come across as quite inhuman, not least because of the sinister nature of eugenics, the Galton you get to know in this book is a mentor to both of these people who latch onto different parts of his work. And he tries his best to encourage them, and likewise to keep them getting along. So throughout the later 1880s through the 1890s, Weldon and Bateson developed these contrary research programmes, both of them inspired by Francis Galton, but heading in quite different directions. And there's increasing tension between them as well. And one of my little discoveries in the book was to find out that the meeting that was held at the Royal Society in the mid 1890s where they first publicly disagreed with each other in a live setting, that meeting was put on only because the Royal Society was worried that its meetings were boring and they needed to liven things up! So they were deliberately pitted against each other. And it's really painful to read their responses. It's, you know, one of those situations where people end up afterwards wondering whether the fact that someone didn't say hello was because they were snubbed. You know, it got really, really fractious.
William Bateson
Greg: So we enter 1900 with these two men, former friends turned frenemies, developing not just different, but in some ways contrary research programmes. The one, William Bateson, is based at Cambridge where he's kind of hanging on by his fingertips. He doesn't really have a proper position. The other, Weldon, is based at Oxford, where he has the glittering role of Linacre professor. I mean, generally, Weldon did better professionally than Bateson did, and that can't have helped their relationship.
Kat: One of the things I love that you mention in the book, you've got some excerpts from their letters, and Weldon does come across as quite spectacularly bitchy. Because you really get the impression as you say that Weldon is really into measuring these very, very detailed differences in many, many, many organisms of a species whereas Bateson's a bit like, "Right, I'm going to go and find some examples of something that show these big changes!"
Kat: And there's a lovely quote from a letter where basically Weldon is saying like, "Ah I can't write anymore! My hands hurt, I've measured 160 crabs today and my hands hurt!" Like that sort of really sly dig at the fact that Bateson hasn't measured anything much.
Greg: Yeah, so Bateson's major book is published in 1894 about discontinuity as a major theme, a neglected theme in biology. And it's a big book and it's full of example after example after example of oddball organisms, you know, showing that you can get organisms with an extra digit, for example. And Weldon publishes a review of this in Nature, and he also has a correspondence about it with Bateson.
Greg: And part of his critique is to say, "Well, yeah, you can find , these oddball organisms and sure, you know, they happen and they're important, but the problem is you've collected all of these from museums. And, how does something get into a museum? It gets into a museum precisely because it stands out from the background!"
Greg: And so, there's Bateson's research programme basically strolling around museums, but what he doesn't show you is how we should interpret that museum-y oddball organism in the light of all the other organisms that weren't collected.
Kat: So all of this kind of comes to a head in 1900 and we've talked about this story on the podcast before whether it's a legend or whether it's true that Bateson's taking the train to go and deliver a lecture and he's - as we all do as academics, we've taken a bunch of reading that we're trying to get through - I guess going through it on the train, and one of those papers is Mendel's paper, so the legend goes. And he reads it and he's like, "Oh my god, this is the thing, like, this is the idea!" However true that is, you know, it's now told as a story, but Bateson gets his hands on Mendel's paper and Mendel's ideas and the kinds of people that are talking about these ideas - it finally gets to him. And it really gets to him.
Kat: So how does he then bring that into his ideas and his conceptions of heredity.
Greg: Well, so let's take this moment to, in a public service way, correct the myth about what Bateson read on that train ride. So it's absolutely the case that Bateson read something really important as he travelled from Cambridge to London to give a lecture at the Royal Historical Society.
Greg: But what the historian Bob Olby showed some years back was that it almost certainly wasn't Mendel's paper that's Bateson read. But instead, a paper by one of the re-discoverers of Mendel's paper, the Dutch botanist Hugo de Vries. And it was in that spring of 1900 that de Vries papers began to appear.
Greg: When Bateson gave his lecture - the lecture was a lecture about heredity, and it was mostly about how Galton's work, including the recently framed 'law of ancestral heredity', had opened a new era in the study of inheritance. And the law of ancestral heredity basically says that you can analyse the inheritance of a character as due to the parents for half of it, the grandparents for a quarter of it, the great-grandparents for an eighth of it, and so on back, right? So now over the next two years, Bateson goes from seeing Galton's Law as the big story and Mendel's Law - as he quickly finds his way to Mendel's original paper - as a kind of useful extension to reversing all of that to Mendel's Law becomes the foundation. Mendel's Law is what we've been looking for. Mendel's Law is what - Darwin himself would have given it all up for had he been able to encounter it at the time.
Greg: Mendel's Law is so attractive to Bateson in part because coming out of his work on discontinuity in the mid 1890s, he'd more and more been concentrating on characters that didn't blend when you crossed organisms: either you get the whole of the character version or you get nothing. That's exactly what he finds in Mendel's paper, so that's immensely attractive, but it's also quantitative, not in the heavy duty statistical ways that Weldon's work is, but in ways that look attractively professional, and it's experimental.
Greg: So it fits beautifully with what he was doing all along. But he rapidly, not just turns Mendel's paper into the basis for a flourishing research programme at Cambridge, initially with his ally there, the botanist Becky Saunders, but increasingly with more and more students who join , but as something which is teachable.
Kat: I would also add that the Punnett Square - we've done a previous episode talking about Reginald Punnett and the Punnett Square - it's the thing that we all do when we learn genetics, you draw a square and you've got big A and little a and all these characteristics coming together. It's very, understandable to a school child, you know, you can really grasp it and you can see it. And I do find it incredible that literally in just two years, Mendel's paper's gone from being this sort of curiosity and it's, you know, it's about peas, a law valid for peas, to suddenly it's like it's the Bible of this new science of heredity. And I really get the sense in the book of how people are, they're searching to use it as an explanation for everything. And you just have to like add layers of complexity, like there are multiple alleles and there's all, like you say, all these kind of mathematical blendings and graphs, and how it can all come together to explain things.
Kat: But then, you have Weldon who says, you know what guys, I don't think it's like this, and this comes to your picture of peas - how does the pea picture, and Weldon saying like, "Wait up, I don't think this actually has the explanatory power that you think it does!"
Greg: Well, let's first talk about, as you say, the extraordinary achievement of Bateson and his allies like Punnett in making Mendelism an invincible research programme. And part of what anyone getting a really successful research programme off the ground has to do is to be able to protect it from getting refuted too easily.
Greg: And Bateson is just kind of amazing at coming up with a whole raft of what a teacher of mine used to call "exculpatory explanations". So, you know, why it is the theory didn't work out in the ways that you expect. And the quality of Bateson's exculpatory explanations are such that they just create more questions within the research programme.
Greg: So you have this immensely fertile research programme where if your next result fits with what you expected. Brilliant! And if it doesn't fit, that's brilliant too! Because it means there's something more to find out, some new way of extending the baseline principles. And Bateson succeeds in energising, first, an ever growing community of researchers at Cambridge, and then more widely in carrying forward this programme and carrying it forward practically as well into agriculture and into society. So that's the context in which William Bateson in 1904 in Cambridge as president of the British Association for the Advancement of Sciences Zoology section gets up to give this kind of horizon touring survey of what Mendelism had been up to. And it's just triumphant! And it ends by saying, so what's the use of this new knowledge we have about inheritance? And he emphasises two things. He emphasises first of all it's going to change agriculture because now it's going to be scientifically led in a way that it's never been before, the breeding of animals and plants. And it's going to change everything socially. Because, Bateson's emphatic about this, now we understand that whatever we do, when it comes to sanitation and education, it's all for naught unless we fix 'the stock'.
Greg: So the message that "heredity is destiny", and furthermore the message that "the rest of you can't handle my truth because I'm a geneticist", that starts right there. It's part of Bateson's message right from the start, that this new science has a harsh social message. And it's time to give up on old illusions.
Greg: On the other side of all of this, we have W. F. R. Weldon watching and thinking, "No!" And he's thinking no, because he, coming out of that Cambridge school of reconstructing evolutionary trees, had gone deep into the study of development, the study of embryos. And in Weldon's view, if there was one major lesson coming out of state-of-the-art biology at the turn of the century, it was that tissues express their capacities in contexts, in environments. It's never the case that some tissue just has some property, as one could read the Mendelians are saying, right - that if you've got a yellow-making factor, the pea is going to be yellow ,no matter what. That it's a kind of absolute property, right? That if you've got the factor for it, you've got the character. In Weldon's view, state-of-the-art biology completely repudiated that perspective. It's always the case that context matters.
Greg: And so, as he begins developing his critique, after, first of all publishing that 1902 paper - which upsets Bateson very much, and Bateson responds ferociously, right, so the game is on - but as Weldon begins developing his perspective, he isn't merely, as it were criticising Mendelism, you know criticising the over homogenisation of what we actually see, right, criticising the explanations. He's also asking himself, "Well, what is the case? How should the science of inheritance proceed?" So we have with Weldon someone who thinks that the starting point for a 20th century science of heredity worth having - which is experimental, which is quantitative - is one which is going to take absolutely seriously the role of environment in modifying the effects of inherited characters, because that's how inherited characters work in general. Yes, it's true that you can artificially strip out complexity from the internal environment, strip out complexity from the external environment. And then you can get Punnett Square simplicity. And that's not uninstructive, but what we mustn't forget is that that's a special case. That's what we get when we strip out all that complexity.
Kat: The analogy that I really like, that you use, is that it's almost like the Mendelian genetics, the Punnett Square version of understanding this. It's kind of like Newtonian physics, you know, you can teach it to a teenager, you can do some calculations, it's got some explanatory power, but it's you have to sit back and go like, "Of course, we know the world doesn't actually really work like that."
Kat: And I'm sure anyone who's done genetics at school and done the Punnett squares and learned about Mendelian characteristics, and then just like, looks around and looks at their own family is it doesn't work like that!
Kat: And today, this idea that it's nature plus nurture, it's variation, it's ancestry, it's environment - I think we kind of take it as given, but it's interesting to know that there was this time when that was actually not the prevailing thought.
Kat: And it's interesting in the book as you're sort of outlining these two parallel ideas about how the world works. Weldon's putting them all together in his big book and he's publishing papers and he's giving lectures and you're like, yay, go Weldon it's starting to go really well! And then in 1906, he dies really young from pneumonia, and so what's the fallout from that?
Greg: Well, yes so at the age of 46, it's all over for Weldon with the book that he was very close to finishing, setting out his alternative perspective, unfinished. And therefore unpublished. And so it's lain in the archive at UCL all these years, getting occasional attention from some historians of science, but nothing beyond that.
Greg: And on the one hand, it raises what if questions, which I pursue at some length in the book, because you have someone whose published work doesn't give anything like the indication of the depth and interest of what was going to come out in that book. The published work is, for the most part, kind of nay-saying, to the point where it can look like nitpicking. Okay, peas aren't just green or yellow, so what, right? You've got this magnificent research programme which is explaining everything. But what you appreciate when you spend time with the Theory of Inheritance manuscript - that was the title on it - was that Weldon came close to showing, at a moment when there was still play in the system, that we could have a science of inheritance which took as its central lesson that genes have variable effects depending on contexts, internal and external, right, which we know to be the case. And we know now to be generally true! And for a thoughtful, well-informed biologist at the very start, that was also the case. So we came really close to that at least being a possibility.
Greg: And I show in the book too that just toward the end - he didn't know it was the end, but that period of Weldon's life, Bateson was getting rattled. You know, Weldon had presented these ideas in lectures at UCL, and Weldon was beginning to score points. But it didn't happen. And I think the analysis of what happens scientifically and culturally because that moment of play in the system disappears and we just get the monoculture, intellectually, that we're familiar with - in which, you know, when it's time to talk about inheritance, we start with Mendel's peas. And then we go off from there in all kinds of ways, but we start there, that anchors student understanding, and some of those students grow up to be scientists, and it continues to anchor their understanding.
Greg: I hope that one of the takeaways for readers from the book is a sense that there are more options for teaching genetics now. In part because they learned there were more options back then, at the very beginning. It wasn't a foregone conclusion that we would end up with our knowledge of inheritance organised around the idea that in the first instance genes come in these two versions, dominance and recessive, and they're associated with these unit characters, you know, yellowness, greenness, roundness, wrinkledness, cystic fibrosis, black... That categorical thinking I think is problematic, it's problematic scientifically and it's problematic socially. And so the thought that actually in attending to the role of elementary Mendelism, in entrenching all of that, we could find that we've got something that we can actually change, I think is an important one.
Kat: I do want to end by drilling into that because we've previously on the podcast run an interview with Brian Donovan. This was part of the Adelphi Genetics Forum symposium looking at the legacy of eugenics. And he's been looking at the impact of teaching in this very deterministic, Mendelian way on just making children, who then grow up to be adults, see the world in this very genetically deterministic way, whether it's in terms of eye colour or race, or intelligence, or any of these other traits that we now know to be complex, multigenic, influenced by the environment. And that really matters, because that is shaping your view, your attitudes and, you know, the policies and the way the world works in the future.
Kat: So to end, what would you like to see in a Weldonian curriculum for genetics? Where should we start? How should we be teaching genetics if we, you know, maybe not get rid of Mendel at all, it's an important historical note, I'm not saying we should cut him out and never talk about him. But what does a Weldon-first genetics curriculum look like to you?
Greg: Well, it's an amazing period, I think, for getting into just these questions, because when my collaborators and I first posed that question to ourselves, you know, the questions that we were just discussing: what if Weldon had lived long enough to publish that book, what would have been different?
Greg: And I realised that I can't go back, you know, literally, and find out what happened! But I can imagine what an introductory textbook would look like now, if it came out of the past in which Weldon's ideas had had that chance to circulate and to gain some purchase. And so, well, it wouldn't begin with Mendel's peas, that's for sure. And it occurred to us that it would be more in keeping with the spirit, both of Weldon's work and with what was known in the 21st century, to start with something which is more representative of the role that genes play in the kinds of conditions that students will actually need to think about over the rest of their lives - like the role that a gene plays in the condition of a heart, of a human heart. Inheritance means development, it means environments, it means variability. And so when we introduce the role that a gene plays in the condition of a human heart, the student sees the gene as one of about 12 sources of causal influence on the state of a heart. Genes are in the mix, of course they're in the mix, but along with diet, stress levels... Once that picture is built up for the student of causal complexity, the thought that there might be a gene for cardiovascular disease just seems a nonsense.
Greg: So we thought, that's the place to start. And then from there, you emphasise at every possible opportunity this theme of interaction, of context mattering, that context matters and variability matters, that we should be actually interested in real-life variability rather than some idealised, fictionalised form of it. And so we imagined this class, and then we got, amazingly enough, the funding to put it on. And what we found was that when we assessed students doing our Weldonian curriculum and students doing the traditional biology curriculum on their attitudes to the idea that heredity is destiny, that genes are kind of super causes, what's called 'genetic determinism', what we found was that students doing the traditional course came out of it unbudged. That they were as deterministic about genes on average at the end of teaching as they were from the start. By contrast, students came out of the Weldonian course on average less deterministic about genes.
Greg: And at least with the genetics teachers I've talked with, that's what they want! And so it's sort of a thrill to think that going back to history and thinking afresh about why things turned out the way they did and whether they might have turned out otherwise, opened up a new option for the teaching of genetics in the age of genomics and epigenetics. And I think if the work that I've done historically helps to light up that question in people's minds and give them courage to experiment with new ways of teaching, that would be really exciting.
