28 July 2021

Molecular evolution pioneer Richard Lewontin dies at 92

 

Richard Lewontin (1929-2021)

Molecular evolution pioneer Richard Lewontin died at 92. His ground-breaking publication was The Genetic Basis of Evolutionary Change (1974). In 1979 he wrote together with Steven Jay Gould the famous article "The Spandrels of San Marco and the Panglossian Paradigm: A Critique of the Adaptationist Programme". He was also known for his Marxist writings criticizing genetic determinism, social inequality and racism: Not in Our Genes (1984, together with Steven Rose and Leon Kamin); Biology as Ideology: The Doctrine of DNA (1993); The Triple Helix. Gene, Organism, and Environment (2000);  and It Ain't Necessarily So. The dream of the human genome and other illusions (2001).

To understand what was so revolutionary about Lewontin's contribution to evolutionary biology, we need to go back to the time before DNA sequencing. Today we see thousands of SARS-CoV-2 sequences being published almost on a daily basis. We can follow the spontaneous origin, spread or disappearance of new variants over the planet. Variation is the cornerstone for Darwin's theory. But the only variation available to Darwin was morphological variation. When Lewontin started his research in the mid sixties certain variations of proteins were detectable by a technique called electrophoresis. This technique could detect protein size differences and differences in electrical charge. Lewontin applied this technique to detect mutations in natural populations of Drosophila. That is, mutations that changed the size or electrical charge of a protein compared to the wildtype protein. In this way he could measure the degree of heterozygosity. Heterozygous refers to having inherited different forms of a particular gene (or protein) from each parent. Lewontin and Hubby found to their surprise that an average individual was heterozygous at 12% of its genes. The other 88% is homozygous (two identical copies of a gene).

Why is this so important for evolution? Suppose there was no genetic variation in natural populations. All individuals are homozygous, as if they were clones. Or identical twins. Then natural selection could do nothing. No evolution. But as soon one of the two copies of a gene has mutated, natural selection could favour one over the other. Textbooks say: "variation is the raw material for evolution." Darwin was right about that.

This study was soon followed by many others. The results were always: every individual in a population is genetically unique because there are potentially hundreds to thousands of variants of each gene and each individual harbours different combinations of all those gene variants. That was big news at the time. It transformed the way scientists think about evolution.

Researchers wondered why all those variant forms were not eliminated? Why don't we see only the wildtype? Are they random variations with no effect on fitness? Why did natural selection not eliminate them? In other words scientists at the time worried there was too much variation. Natural selection is a costly process ('the cost of natural selection problem'). Selection requires differential survival or reproduction. Later these questions led Kimura to propose his now famous 'The neutral theory of molecular evolution'.

Still later protein and DNA sequencing revealed far more differences between individuals. The first study of genetic variation using DNA sequences was published in 1983. That is 30 years after Watson and Crick published the structure of DNA. The rest is history. Today the study of evolution is the study of variation at the DNA level. 

The popular science books I mentioned above are within a different category. Difficult to summarize. These books are a mix of political activism, science criticism, and popular science. Often written from a political perspective or highly critical to mainstream scientific views on adaptation, genetic determinism, development, and the role of the environment. Undoubtedly, the most famous is the article he wrote with Steven Jay Gould: 'The spandrels of San Marco and the Panglossian paradigm: a critique of the adaptationist programme' (1979). 

 

See also an obituary of Lewontin in Nature: Richard C. Lewontin (1929–2021). Pioneer of molecular evolution who campaigned against biological racism.

 

What the textbooks say about Lewontin

  • Douglas Futuyma (2005) Evolution. Lewontin is not in the index, but present in Literature list and a good discussion of the importance of his work can be found in the paragraph 'Genetic variations in proteins', page 203.
  • Stephen Stearns, Rolf Hoekstra (2005) Evolution: an introduction. Lewontin is not in the index, not in the Literature cited, but he is mentioned on page 31: "... Lewontin and Ayala, for gene products detectable by electrophoresis, ... have shown that a great deal of genetic variation is present in natural populations for many types of trait and organism." (page 31).
  • Freeman and Herron (2007) Evolutionary Analysis, 4th Edition. Lewontin is in index and discussed in paragraph 5.4 'Measuring genetic variation in natural populations'. 
  • Nicholas Barton et al (2007)  Evolution. Lewontin is in the index and S. J. Gould, Lewontin (1979)  is discussed in the text. 
  • 'Strickberger's Evolution' (2008). Lewontin is not in the index but in Literature cited. I could not find him in the text. 
  • Carl Bergstrom, Lee Alan Dugatkin (2012) Evolution. Lewontin is discussed in 8.5 'The Neutral Theory of Molecular Evolution', page 276. They consider the work of Lewontin as a prelude to The Neutral Theory of Molecular Evolution. 
  • Carl Zimmer, Douglas Emlen (2013) Evolution. Making Sense of Life. They have replaced Lewontin with modern day examples of genetic variation in populations.


24 comments:

  1. "Today the study of evolution is the study of variation at the DNA level".

    This 'raw material" idea has come a long way!

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  2. Thank you. In fact the statement "Today the study of evolution is the study of variation at the DNA level" is a bit of a simplification! Better is: evolution cannot be studied any more without studying DNA at the molecular level. Of course: morphological variation is still important. But not in isolation.

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  3. "evolution cannot be studied any more without studying DNA at the molecular level."

    'raw material': that just was the trope that was meant to promote the all pervasive role of Natural Selection as the driving force of evolution, as the central 'force', as the agency that 'sculpts', 'builds' - or what metaphores they've come up with.

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  4. Hi, did you know Lewontin? Have you read any of his critical and/or 'political' writings? It seems they are the sort of books you would like?

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  5. The [...] must either be founded on our actual experience in dealing with real bodies of sensible magnitude, or else deduced from the molecular theory of these bodies, on the hypothesis that the behaviour of bodies consisting of millions of molecules may be deduced from the theory of the encounters of pairs of molecules, by supposing the relative frequency of different kinds of encounters to be distributed according to the laws of probability. The truth of the [...] is therefore a statistical, not a mathematical, truth, for it depends on the fact that the bodies we deal with consist of millions of molecules, and that we never can get hold of single molecules.”
    Guess who.

    See also Fisher 1930. Genetical theory of evolution about his own theorem.

    ReplyDelete
  6. Maxwell on Heat and Statistical Mechanics.
    [...] = second law.

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  7. However, I don't see how this cryptic quote could be relevant, because Lewontin did not mathematical work, on the contrary, he did biochemical work on proteins and enzymes and how to detect variation of those proteins in the lab. And he got results and data. He made progress because he used new techniques and uncovered a hidden world of molecular variation of organisms in the wild. He started a whole new field of evolutionary research. He increased our knowledge. That is progress. That's way he is important. I wish I had written that in my blogpost.

    ReplyDelete
  8. relevance?

    Okay, let's try

    Mathematical truths are completely beyond the reach of biology. But that does not mean that statistical truths make biological sense (see Fisher, 1930).

    Lewontin's research confirmed the belief of his teacher Dobzhansky - and indeed of the founders of the new synthesis, Haldane and Fisher - that there is always variety from which natural selection can draw when needed - one does not have to wait for the right, lucky mutation, let alone the hopeful monsters: there is enough raw material, at least enough for statistical truths about variation ( in standing gene pools).


    At the same time, Lewontin (with Gould) had to admit that if you only start with raw material and statistics (about frequency shifts) you will inevitably end up with tons of spandrels - more than there are in the whole San Marco.

    There once was an interesting discussion about statistical, mathematical and biological truths between the young R. Lewontin and the mathematician P. Schutzenberger at the 1966 Wistar conference.

    The analogy Maxwell (who didn't like Darwin's idea by the way) suggests is even more relevant given current research on 'DNA at the molecular level', which you could call partly Lewontin's legacy.

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  9. Indeed, spandrels are relevant in the context of a discussion about Lewontin. But:
    "...you will inevitably end up with tons of spandrels - more than there are in the whole San Marco. " ( or in the whole universe?
    tons of spandrels?
    Could you give us a few (tons of) spandrels in the human body?
    What about the most essential organs: brain? lungs? hart? muscles? kidney? liver? bloodvessels? stomach? gut? eyes? teeth? adaptations or spandrels?

    ReplyDelete
  10. There are tons of spandrels in our brains alone, chemical, anatomical, physiological, neurological spandrels.

    And frequency shift models (population genetics Haldane Fisher style) don't come close to explaining. Just take the size of our brain, for example. There are only just so stories.

    Now that we're on the subject

    Your suggestion that only the spandrel story should be relevant, is completely off.

    So, it might be a good idea to update your knowledge with some recent examples:

    Rama S. Singh, Decoding "Unnecessary Complexity": A Law of Complexity and a Concept of Hidden Variation Behind "Missing Heritability" in Precision Medicine, Journal of Molecular Evolution (2021). DOI: 10.1007/s00239-021-10023-3 (Singh dedicated his paper to his mentor Lewontin)

    Yona AH, Alm EJ, Gore J. Random sequences rapidly evolve into de novo promoters. Â Nat Commun. 2018;9(1):1530. Published 2018 Apr 18. doi:10.1038/s41467-018-04026-w

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  11. A: "There are tons of spandrels in our brains alone" aha! so your brain is a spandrel? tons? Please give me one! Please!

    So, this "Unnecessary Complexity" is this an argument against Darwinian evolution? the theory of evolution in general?

    So, this "Unnecessary Complexity" is this an argument for Intelligent Design?

    Random sequences rapidly evolve into de novo promoters:
    "We studied de novo evolution of promoters in Escherichia coli by replacing the lac promoter with various random sequences of the same size (~100 bp) and evolving the cells in the presence of lactose. "
    That is a very elegant experiment!!!

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  12. As I said, our big brains are one big spandrel, and they are filled with tons of other spandrels (that frequency shift models cannot explain- not even describe- let alone just so stories can).

    Just to name a few (recently identified):

    -The language-relevant connectome. Science 366, 55-58 (2019) October 4, 2019

    -The dopaminergic VTA function elucidating a critical aspect of the brainstem-cortical interaction for consciousness. PNAS 2021 Vol. 118 No. 30 e2026289118 https://doi.org/10.1073/pnas.2026289118

    Some darwinists ( f.e. D. Dennett) argue that consciousness is an illusion. So there are even phantom spandrels in our heads, supposedly an evolutionary advantage.

    You better read articles before commenting to understand why Singh is dedicating his research to Lewontin and leave out clinchers like 'Intelligent Design' and 'elegant research'.

    In short, you better take comments seriously if you want a serious discussion

    ReplyDelete
  13. If I ask for naming specific spandrels, than copy&paste article titles is no answer.
    And don't distract by throwing in consciousness, Dennett, etc..

    A: "..and leave out clinchers like 'Intelligent Design' "
    So, you are not interested in arguments for or against evolution, nor for or against Intelligent Design. (?)
    but at the same time you identify Dennett as a darwinist in stead of a philosopher.

    So if you say your brain is a spandrel and full of spandrels than you mean your brain is not an adaptation?

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  14. you didn't even look at the references:

    The language-relevant connectome
    and the
    dopaminergic VTA function in the brainstem-cortical interaction

    are not article titles, but names of brainprocesses/functions or spandrels

    you can't seriously talk about brains and brain functions (not even about spandrels) without language, obviously one of our most important brainfunctions

    same with consciousness. If that's a 'distraction', our dopaminergic VTA function must be one big distraction too.

    Dennett is a die hard darwinist philosopher

    When I "say our brain is a spandrel and full of spandrels", I simply mean that no model of population genetics
    or loads of just so stories have anything to say here (see Evolutionary Psychology positioning itself as 'the new study of the mind'. Or, even worse, this so-called memetics)

    Why didn't you mention Lewontin’s work on LD that forms 'the underpinning for the method of Genome Wide Association Mapping',
    according to B. Charlesworth, another student of his. Heredity (2019) 123:44–49 https://doi.org/10.1038/s41437-019-0195-1

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  15. "When I "say our brain is a spandrel and full of spandrels", I simply mean that no model of population genetics "
    aha! that is a very cryptic way of expressing oneself.

    "...one of our most important brainfunctions..."
    aha! the brain has functions! so these functions are not spandrels?

    take home message: no spandrels of San Marco without a cathedral in the first place. There must be a cathedral first.
    Or do you claim the cathedral of San Marco has no function?

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  16. “So if you say your brain is a spandrel and full of spandrels than (sic) you mean your brain is not an adaptation?”

    Yes, because "plausible stories can always be told" about our brain as one big heap of accumulated evolutionary advantages.

    To paraphrase a worn-out trope:
    Nothing in brain-science makes sense except in the light of BVSR- Blind Variation and Selective Retention.

    It’s like in 1 Thessalonians 5:21: "test everything. Keep what is good, and stay away from everything that is evil" (some would argue that it is Darwin’s most important contribution to science and history to replace god by nature).

    The gene pool proposes, natural selectionrates disposes. Or better: “Not to be misunderstood, perhaps biologists should stop referring to “natural selection,” and instead talk about differential rates of survival and reproduction.”—Richard Lewontin, “Not So Natural Selection,” New York Review of Books, 2010

    Language does have different functions: e.g. horizontal information transfer so we don’t have to wait for the next generation (gene pool) for survival and reproduction- a tremendous advantage indeed.

    But advantage doesn’t explain function. It’s the other way around: function explains (the scope, the reach of) the advantage. And language does have a very large scope or reach (extended phenotype if you like).

    Same with all other functions of the brain, e.g. locomotion, control, sentience, attention, memory, planning, prediction, foresight, intentionality and to mention just one more: the production of information, knowledge, science.

    "Well, a priori, one should expect a chaotic world, which cannot be grasped by the mind in any way . Even if the axioms of the theory are proposed by man, the success of such a project presupposes a high degree of ordering of the objective world, and this [also] could not be expected a priori. That is the ‘miracle’ which is constantly reinforced as our knowledge expands."

    May be, like Lewontin, we should be more modest about the reach of our talk, or'models', of differential rates of survival and reproduction.

    To take home: there isn't even the beginning of the building of the (basilica of) the San Marco. Don't get carried away by your metaphors.

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  17. Anonymous said
    "And frequency shift models (population genetics Haldane Fisher style) don't come close to explaining. Just take the size of our brain, for example. There are only just so stories."

    this is typical for your way of thinking: take a the name of some theoretical work in evolution, add some famous names, and claim it does not explain X, X= one of your favourite unexplainables.
    The formula is: The evolution theory cannot / can never explain X,Y,Z. The statements are always vague, no details. Always unfair.

    You don't care whether that particular theory you refer to is intended to explain you X,Y,Z. You claim "There are only just so stories" is itself a just-so story because you don't give further information; you don't take the trouble to demonstrate it. It is just a claim. A just-so statement.

    The ultimate just-so story is: God created everything. It explains nothing. It cannot be tested. It does not predict anything or for many believers God predicts everything. You can give any definition of God you like. There are no constraints. God/Intelligent Design is the ultimate just-so-story. It is not even a plausible story because it does not answer the question Who created God? These questions cannot be investigated at all.

    I am not a brain researcher; most evolutionary biologist are not brain researchers, so let's conclude with the ultimate just-so story: God created the brain! And GOD created language! of course.

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  18. "The statements are always vague, no details. Always unfair."

    I already concluded August 5, 2021 at 1:42:00 PM GMT+2 that "you didn't even look at the references"

    Same again this time.

    But you can remedy your shortcomings as yet as soon as possible, so you know who you're arguing with.

    And please keep your straw men for others

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  19. You didn't deny you are an ID-ist. You did not confirm God/ID is the ultimate just-so-story ever invented. suspicious.
    You keeping throwing around article titles without proof you read them yourself.
    "And please keep your straw men for others":
    you didn't bother to tell what straw men and why it is a straw men. As usual you are not precise, you are not explaining what exactly you are trying to say.

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  20. By the way, I can't remember you ever asked me for advice about biological, or evolutionary subjects. Add to that, that you refuse to study textbooks. Being a non-biologist. The result is that you are unable to give a correct description of what natural selection is. Notwithstanding this, you behave as if you have profound knowledge of evolution by throwing around quotes. I suspect all this is just bluff. Bluff your way in evolutionary biology! Criticizing a research field you never studied professionally. You have to know the science before you can criticize the science.
    I am afraid you have a pretty big disdain for biologists in general and in particular for evolutionary biologists. You never said anything positive about evolutionary biologists as far as I can remember. Because of all this it is nearly impossible to have a friendly and fruitful exchange of thoughts.

    If you really hate just-so-stories, than you have to be happy that Darwin replaced the thousands years old collection of just-so stories called 'creation' which can be found in the bible. If you think those just-so-stories are better than Darwin, say so please.

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  21. You don’ need to be a brain researcher to see the limits of your Panglossian universal truths, because Lewontin wasn’t one either.

    See: (1998). The evolution of cognition: Questions we will never answer. In D. Scarborough & S. Sternberg (Eds.), Methods, models, and conceptual issues: An invitation to cognitive science, Vol. 4, pp. 106–132). The MIT Press.

    "Tough luck"!

    To be precise again and to give another concrete example, ‘explaining what exactly [I am] trying to say’, I’d just throw 'around' yet another ‘article title’: Science, DOI: 10.1126/science.aax2537

    “There are many situations in which biological complexity means that detailed population genetic models are intractable (2019, B. Charlesworth. He is another student of Lewontin’s, as I already told you).

    Needless to say, of course, that just so stories won’t work either.

    You better read all my refs yourself first this time, because that’s the only way your own contrived ‘prove’ can work out at all – besides I don’t need to bother to tell you ‘what straw men and why it is a straw men’

    If you really think that criticism of Darwinism implies believing in some god or in fairy tales, then you must indeed also think your own ID straw man isn't one.

    TINA, you think: There Is No Alternative?

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  22. 1. I can't remember you ever asked me for advice about biological, or evolutionary subjects. Add to that, that you refuse to study textbooks. Being a non-biologist. The result is that you are unable to give a correct description of what natural selection is.

    2. Notwithstanding this, you behave as if you have profound knowledge of evolution by throwing around quotes. I suspect all this is just bluff. Bluff your way in evolutionary biology!

    3. Criticizing a research field you never studied professionally. You have to know the science before you can criticize the science.

    4. your quotes are an extremely one-sided selection of the evolution literature: always negative, always pointing out failures, shortcomings. Never successes, progress, interesting new discoveries and insights.

    5. I am afraid you have a pretty big disdain and disrespect for biologists in general and in particular for evolutionary biologists. You never said anything positive about evolutionary biologists as far as I can remember.

    6. You are hiding behind TINA (There Is No Alternative), in stead off admitting that you have an alternative: ID. An alternative that is worse. Because it is not a scientific alternative. This explains all your behaviour so far.
    You don't defend ID as an alternative because you can't or you don't have the courage. You are a stealth IDist. That's worse than IDists who openly admit they are ID.

    7. Because of all this it is nearly impossible to have a friendly and fruitful exchange of thoughts.

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  23. Dear Dr Korthof

    I can't judge your memory, but no doubt you can help me figure out why the description of natural selection by Lewontin, I gave you on Friday August 6, 2021 at 11:16:00 AM GMT+2, is not correct.

    May be you think his second definition in that same article, is more correct: “natural selection is artificial selection writ large'?

    Or perhaps you fancy the one by Futuyama and Krikpatrick, (4th edition on p 60) ? . That is, one "Among [the] several slightly different definitions of natural selection used by biologists today”.

    Or may be, you’d rather have another one they give on page 74: “Natural selection—or simply “nature” “ (yet one among other different descriptions they give passim)?

    Yet, you might prefer the definition by Herron and Freeman, 5th edition, p 26): "natural selection just happens, it is an automatic consequence of heritable differences in replication"?

    So, before I start listing all different definitions/descriptions of NS (not to mention all different kinds of NS, e.g. epistatic selection (relevant in Lewontin’s obit, because of his work on linkage disequilibrium (btw not mentioned in the above textbooks)), I’d ask you again, what (different) definition of NS would you think is correct?

    The point is not what I am or what I am not, but what I do say or don't say. Or rather, what I quote, because most of the time someone else said it much better already than I can.

    So much for your first points and your suspicion about my 'behavior' of 'throwing around quotes' To help your faulty memory: you have used this reproach four times now, without answering me on-topic

    Your "Never successes, progress, interesting new discoveries and insights" is also simply wrong, as you admitted yourself Thursday, August 5, 2021 at 9:06:00 AM GMT+2 And you must have missed all my other refs, especially the one about NOVA1.

    My feelings about biologists don’t matter. And show me that I don't "know the science'. This NOVA1 research you mean? Show. Don't yell (pun intended).

    Your innuendo that I must be a ‘stealth IDist’ tells everyhing - about you.

    If you think you can get off that easy, we’ll never get a ‘ fruitful exchange of thoughts’ indeed. Even if you answer point by point.

    Just answer on-topic. All topics I raised, that is.

    ReplyDelete
  24. I advise you to come up with a subject for a doctoral dissertation and then find a professor in evolutionary biology who is willing to accept you as a doctoral candidate.
    I further advise you to be honest about your goals, Right From The Start!
    Good luck!

    ReplyDelete

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