Molecular Evolution Activities

Origins Transcript
The Origins of the Neutralist-Selectionist Debates


The discussion begins with reference to Bryan Clarke's online recollections about his initial views of the neutral theory [Discussion: "The Early Reception of the Neutral Theory"]. This prompts a discussion of whether the origins of the neutralist-selectionist debates should be sought in the earlier selectionist-drift debates, in which Clarke played a major role.

Michael Dietrich: The online discussion of initial reactions to the neutral theory includes responses from some people that I don't think historians have ever talked to. I don't think historians have ever talked to Bryan Clarke about his very important response paper ["Darwinian Evolution of Proteins," Science 168 (1970): 1009-1011, download pdf].

Richard Lewontin: Could I ask a question at this point about how far back you're willing to go? One of the earliest struggles between neutral and selective explanations of a well documented evolutionary situation was the whole snail business. You have the monograph of Maxime Lamotte, which was an attempt to have Wright's generalized system explain what you see in nature. It was a short term evolutionary change, a differentiation between populations. I think you then had the whole English school, which could not stand it, and wanted to make it selectionist. So you already had the stage set, in a way, for the struggle between an adaptive explanation of a well documented microevolutionary circumstance, as opposed to a Wrightian approach. Now, my question to you is, do you want to go back to a non-molecular case (although with single genes—I mean, that's the beauty of it—you had single gene segregation, which explained the whole thing). How far back in the struggle do you want to go?

James Crow: And if you're going to go back, what about Freese and Sueoka, who were there long before Kimura—not long before, but substantially before.

John Beatty: We are interested in the origins of the neutral selectionist controversy.

Lewontin: And so the question is, is the snail thing an origin, or just part of the general "smell of the field?"

Beatty: The important thing would be to recognize it as an origin. Maybe some people would look at the neutralist-selectionist controversies as just an extension of the selection-drift controversies without realizing that there are other ways in—there are alternative origins.

Crow: I think it would be good to go back. On the other hand, as far as Kimura himself was concerned, none of these things ever had any influence on him—I'm pretty sure—in the writing of that paper.

Lewontin: Well, we'll get into that!

Crow: All right, I'll just assert that opinion! Tomoko knows better than anyone else the answer to that question.

Tomoko Ohta: Sueoka's paper was not paid attention to.

Crow: I know.

Ohta: He considered mutational pressure for the genome as a whole, taking the genome as a whole. So, I don't see any priority.

Crow: No, I don't think it had any effect on Kimura either, but it's certainly related in the sense that Wright and Fisher are related.

Beatty: It's an issue for historians, when you are going back to look at the origins of some tradition, or some debate, whether you go back to the first time that it is posed in this way, versus the first time that it was posed in this way and then led to a continuous discussion. There can be independent origins of it, but some that are not followed.

Ford Doolittle: I was a graduate student in the 1960's, but I was a molecular biologist, so the neutral theory struck me as "duh." Because we were used to looking at lots of sequences and saying, "These are the important residues. They must be functional. These others must not matter." So even though I was in Charlie Yanofsky's lab, and he was a panadaptationist—at least at some level—at the same time we could entertain the fact that these amino acid changes that you could see in the spectrum of sequences were neutral. We always said, "What are you guys so excited about, because it's just obvious." So that's another thread that I think predates these papers.

William Provine: Jukes certainly believed that.

Crow: There was a wonderful paper by Cox about that time. [Speaking to Doolittle] I don't know whether he was a contemporary of yours or not. It was by Cox and Yanofsky.

Doolittle: I think he was a postdoc when I was there.

Provine: There is a very crucial issue that distinguishes the snail case from Kimura's 1968 paper. The 1968 paper was clearly directed to very deep evolutionary time.

Lewontin: I understand that.

Provine: And the short evolutionary time that Lamotte was talking about, and that Sewall Wright was talking about, and that in general people were talking about when they spoke of random genetic drift, is completely different from what was in Kimura's mind. Which is why he could consider a model that paid no attention to population size, which had been so closely tied to the idea of random drift before that. So, to me, deep evolutionary time is really different from the sort of random stuff that came before. The "nearly" neutral theory is deep evolutionary time too. The neutral theories were a different kettle of fish, than the old random drift.

Lewontin: That may or may not be, but that is an issue that would suggest that we should not go back to the snails.

Provine: You may want to go back to the snails as part of the backdrop, and I would certainly do that. But you have some new factors coming in here. They are not immediately recognized; people didn't immediately understand this issue of evolutionary time.

Dietrich: I think you are going to have to have the snail cases in there, because when people like Dobzhansky, for instance, read Kimura, and King and Jukes, I'm sure he was thinking more of [Arthur] Cain, and not of Kimura's, and King and Jukes’s work, and definitely not of the biochemists’ work. To understand the response, you have to have these different traditions in there.

Crow: And everybody knows that Wright thought Kimura's theory was nonsense, and said so.

Provine: No. That's not fair!

Lewontin: Let's save this for another time!

Provine: Wright said, "I think you're probably right, but it's irrelevant because I am not interested in that neutral evolution. If it's really neutral, it's uninteresting!" And that's basically what Dick Lewontin said too in his 1974 book. [laughter] You [speaking to Lewontin] did it over and over again; I'll show you in your book.

Crow: The thing that Kimura hated the most was to say that it was true, but that it wasn't interesting.

Provine: I know. He was furious!

Lewontin: That's the ultimate squelch.

Tomoko Steen: Last fall, I mailed a bunch of people, including Dr. Crow, to find out what was the origin of the name, "neutral theory," and also the "neutralist-selectionist controversy." Nobody could really point out what the original publication was where these words were first used. I am really curious to know more about this.

Ohta: I think Kimura's 1968 paper.

Crow: He used the word "neutral" in the paper? I can't remember.

Dietrich: He uses the word "neutral," but he doesn't call it the "neutral theory." People talk at first about "non-Darwinian evolution." When they stop calling it "non-Darwinian," then they start to call it "neutral." Kimura actually goes back and says, "Oh, I don't like that neutral theory name." Rather, he talks about "neutral mutations."

Provine: The problem is that the theory is not neutral. It is very controversial! [laughter] It is anything but neutral. It is a theory of neutral molecular evolution.

Lewontin: [referring to text projected onto a screen] There it is, it's right in the 1968 paper.

Beatty: No, there he talks about "neutral mutations."

Steen: Yeah. Lots of people used the word "neutral mutation."

Beatty: [speaking to Provine] Will, do you think it could be in response to his dislike of the term non-Darwinian evolution? Is that why he came up with a different way of referring to the process?

Lewontin: But this is 1968, and "non-Darwinian" was introduced by King and Jukes in 1969.

Beatty: Right, that's when he starts calling it "neutral theory"—after the King and Jukes paper.

Provine: He knew about the King and Jukes paper in 1968. That's when you [speaking to Crow] brought it to him.

Crow: Is that where he got it?

Provine: You brought a copy of the King and Jukes manuscript to the international congress and gave it to Kimura. Kimura read it, and wrote a letter back to King.

Beatty: [speaking to Provine] Will, will you just quote one of the important passages concerning that from this letter? Will was kind enough to bring this letter along.

Provine: Right after the congress, October 26th, 1968, he writes to Jack, "I am not very fond of the title non-Darwinian evolution. I am sure that any biologist would feel such a concept unacceptable. Would it not be more appropriate to modify the title slightly such as "non-Darwinian molecular evolution" or "non-Darwinian type evolution at the molecular level."

Lewontin: None of these guys ever read Darwin.

Provine: When I asked him about this, Tom [Jukes] rolled his eyes and said, "We actually really liked that title!”

Crow: They wanted publicity and they got it.

Lewontin: That's exactly right.

Doolittle: I remember thinking that it was a publicity stunt.

Provine: He was sure that Dobzhansky would go ballistic.

Jan Sapp: I think that they thought it was an oxymoron. Using "non-Darwinian" and "evolution" in the same sentence at the time seemed like an oxymoron.

Dietrich: So as we're building this site, how do we capture this discussion of origin? Should we try to write a historical overview of it?

Lewontin: As a way of triggering a large amount of discussion and controversy, yes. Any one attempt to distill that will appall a lot of people. It will bring stuff out of them. I think it would be very good.

Dietrich: I developed a site called "Who discovered neutral molecular evolution?" The answer was Morris Goodman in 1961, even before Sueoka and Freese. He says it all very beautifully. And of course it was completely and utterly ignored.

Crow: By himself included. [laughter]

Dietrich: Except, if you ask him about it, he will remind you and send you a reprint of the section.

Lewontin: It's like Leif Erikson discovering North America. [laughter]

Dietrich: Charting out that territory, you find a lot of people who are talking about it before it becomes crystallized.

Provine: It's like "natural selection" before the publication of the Origin. Historically, to me, the actual origins don't make any difference until they have some kind of effect. I don't care if somebody invented it and it was hidden. I could care less.

Lewontin: You just don't want to read Aristotle.

Provine: I love reading Aristotle! But not to find out who first came up with an idea in Greek history. Muller said every idea anyway. I bet you anything that there is some place in Muller where he invented the neutral theory, probably in the 30's or the 20's.

Crow: And if he were alive, he would go to the library and find it!

Provine: And he would read you chapter and verse, or maybe it would only part of one sentence, but bingo it would be right there.

Crow: He spent all afternoon once looking up something that I was perfectly willing to accept on his word that he thought of it first.

Ohta: On the other hand, Muller was serious about adaptation—adaptive evolution.

Crow: Yes, he certainly was an "adaptationist," if that's the right word.

Beatty: Which, I think, complicates the type of history that Dick [Lewontin] wrote of the neutralist-selectionist controversies. According to Dick, the neutralist group supposedly derives from Muller's "classical" position and becomes "neo-classical." And yet we think of Muller as being as arch-adaptationist as you can possibly be, probably even more so than Dobzhansky. To hear it called "neo-classical"as opposed to "counter classical," or "anything but classical," confuses some people.

Crow: This is my view, and we will see if anybody else agrees: Kimura's paper did not come out of the classical-balance argument. It came out of molecular evolution data.

Dietrich: I think the data came from the 1964 "Evolving Genes and Proteins" conference. But I think you can find Kimura saying things very much in a classical tradition: for example, his papers on genetic load.


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