Epigenetics: the return of Lamarck? Not so fast!

I noticed that there’s a new book out by Peter Ward, a biology professor at the University of Washington who’s done a lot of work on nautilus cepalopods. (He’s also written several trade books in biology.) Here’s his new book, and, as you can see, the cover touts epigenetics as “Lamarck’s Revenge” (Jean-Baptiste Lamarck [1744-1829] was a French naturalist who proposed a theory of the inheritance of acquired characteristics.) The cover also promises to show how epigenetics is revolutionizing our understanding of evolution. Click on the screenshot to go to the Amazon site:

The book has been reviewed in several places, and I noticed that while it got a starred review on Kirkus, Publisher’s Weekly called it a “frustrating book” and has this in its review:

Ward references the classic study showing how starvation impacted one and perhaps two generations in the Netherlands following a WWII-era famine, but provides little hard evidence beyond that example. [JAC: see below for a discussion how even the famine study is flawed.] Without a proposed mechanism for such long-lasting effects and without data indicating such effects exist, Ward leaves readers with little more than suppositions.

And that’s the problem with the Lamarckian/evolutionary/revolutionary hypothesis. Environmentally induced changes to the DNA, usually produced by the placement of small methyl groups on DNA that affect what it does, are almost never inherited beyond one or two generations. This lack of stable change means that such environmental modifications cannot form the basis of permanent evolutionary adaptation. Ergo, it can’t revolutionize our view of evolution.  As the prescient Publisher’s Weekly reviewer noted, there’s just no evidence for the heritability of “Lamarckian” changes to the DNA.

I haven’t yet read Ward’s book, and don’t want to judge it by its cover, but the Nautilus site (the name is a coincidence, and that site was funded by Templeton) has reproduced an excerpt from Ward’s book, which is the article below on “fewer species”. Click on the screenshot to read it. And it gives me no confidence that Ward’s book presents a balanced view of epigenetics.

Lamarck’s Revenge, like David Quammen’s new book on phylogeny, seems to fall into the “Darwin was wrong” genre. (Darwin was supposedly wrong because modern evolutionary theory proposes that either mutations or genes transferred from other organisms are the variational basis for permanent adaptive change, and that the environment cannot itself influence DNA sequences in a permanent way. If environmental methylation did produce gene changes that could be both inherited and adaptive, and so spread through species, it would be a major change in how we view evolution.)

I should add that Darwin himself was “Lamarckian” because he thought the environment could somehow permanently modify heredity, and, as Matthew Cobb reminded me, Lamarck thought the changes occurred not through the environment, but through the animal’s “will.” Both men were wrong about heredity, but, as Matthew suggested, Ward’s book might better be called Darwin’s Revenge! After all, Darwin’s ideas were closer to these misguided epigenetic ideas than were Lamark’s theories.

Click and read:

 

Now the title doesn’t say much about Lamarck or the “evolution revolution”, but the article itself does. The title itself refers to work that Ward did with his colleagues on two species of Nautilus. One species, N. pompilius, occurs widely across the Pacific, while the closely related species N. stenomphalus is found only on the Great Barrier Reef. They were distinguished as different species by differences in morphology: they differ in whether they have a hole through the center of their shell, as well as showing big differences in both internal and external anatomy.

Ward, however says that they aren’t separate species because their DNA was identical using DNA-sequencing analysis (my emphasis):

We caught 30 nautiluses over nine days, snipped off a one-millimeter-long tip of one of each nautilus’ 90 tentacles, and returned all back to their habitats alive (if cranky). All the samples were later analyzed in the large machines that read DNA sequences, and to our complete surprise we found that the DNA of N. pompilius and the morphologically different N. stenomphalus was identical. No genetic difference, yet radically different morphology. The best way to interpret this is to go back to one of the most useful analogies in evolution: of a ball rolling down a slope composed of many gullies. Which gully the ball rolls down (corresponding to the ultimate anatomy or “phenotype” of the grown animal) is controlled by the direction of the push of the ball. In evolution, the ultimate morphological fate of an organism is caused by some aspect of the environment the organism is exposed to early in life—or, in the case of the nautiluses, while they slowly develop in their large egg over the course of an entire year before hatching. Perhaps it is a difference in temperature. Perhaps it is forces that the embryo encounters prehatching, or when newly hatched, the small nautiluses (one inch in diameter, with eight complete chambers) find different food, or perhaps they are attacked and survive, i.e., have two different kinds of predators. That’s why N. pompilius and N. stenomphalus are not two species. They are a single species with epigenetic forces leading to the radically different shell and soft parts. Increasingly it appears that perhaps there are fewer, not more, species on Earth than science has defined.

Well, the differences might not be genetic, but they might not be epigenetic either: the environment could simply change the development of the organism in different places without methylating or modifying its DNA in a heritable way, just as a plant given lots of fertilizer in one plot will grow taller than a plant grown without fertilizer in another plot. There’s no indication here that the differences in morphology of the two Nautilus species are caused by methylation of the DNA or histones, or by small RNA molecules—the three ways Ward says the environment might modify genes in a permanent way.

More important, when I looked up the paper on which this statement was based, I found, contrary to what Ward implied, they didn’t look at a lot of DNA in the two species, finding it identical. The paper (click on screenshot below), published in 2016, looks at only two genes in the mitochondria, and none from the nucleus:

An excerpt from the paper above:

Here, we report the genetic analysis of mitochondrial genes cytochrome c oxidase I (COI) and 16S rDNA, commonly utilized genetic tools for the phylogeographical studies of marine invertebrates, including cephalopods (Anderson 2000; Anderson et al. 2007; Dai et al. 2012; Sales et al. 2013a) from individuals across the known locations of Nautilus populations (Philippines, Fiji, American Samoa, Vanuatu, and eastern Australia – Great Barrier Reef). We chose COI and 16S because of their variability and success in past studies, and to align with sequences generated for this study with previous nautilus studies (Bonacum et al. 2011; Williams et al. 2012). We neglect nuclear genes (e.g., 28S or histone 3) because sequencing efforts have been limited in nautilus, precluding comparative analysis with past studies, and have been shown to be relatively uninformative for phylogenetic studies within this genus (Wray et al. 1995).

Now while the two species might indeed be one, you can’t conclude that from the identity of just two mitochondrial genes. And the Nautilus article at the top implies that a lot of DNA was examined. There may be substantial differences in other parts of the DNA that produce the morphological differences between the two (ergo these differences having a genetic rather than an epigenetic basis), and may even lead them to be reproductively isolated, ergo being two biological species.

I may have missed another paper looking at whole-genome sequences, but I doubt it. To me it seems that Ward is exaggerating his findings, and also implying that they extend to many species on earth, which might not be “biological” species because their differences are based not on DNA, but on developmental differences induced by the environment (and perhaps inherited via methylation). That might be true, but it’s an unwarranted extrapolation from a study of one organism.

Now Ward does mention one well known and important epigenetic property: the development of different cells and tissues in a single organism is often set off by epigenetic modifications that are themselves coded in the genome (i.e., the DNA of gene A says, “turn on/off genes B, C, D, and E under different internal environments”). Those differences are inherited through different cell divisions, which explains why, though all the cells in the body are genetically identical, they do different things and form different tissues. And those epigenetic changes are coded into the organisms’s DNA; they don’t come directly from the environment.

But that applies only to development of a single organism. It’s a very different thing to claim that environmental modification of the DNA of an organism is passed on through its gametes to its children, grandchildren, and so on, for that’s the only kind of environmental modification that can be involved in evolution. And the evidence says that this isn’t likely to happen. As I’ve said  repeatedly, methylation changes (and Ward notes this) are usually wiped out completely when gametes are formed, and we know of NO adaptation that is caused by environmentally-induced methylation of DNA or histones.

Yet in his popular article, Ward goes on to imply that this really does happen, and happens in human evolution as well. Here are a few excerpts (my emphases):

The methyl molecules are not physically passed on to the next generation, but the propensity for them to attach in the same places in an entirely new life-form (a next-generation life-form) is. This methylation is caused by sudden traumas to the body, such as poisoning, fear, famine, and near-death experience. None of these events come from small methyl molecules, but they cause small methyl molecules already in the body to swarm onto the entire DNA in the body at specific and crucial sites. These acts can have an effect not only on a person’s DNA but on the DNA of their offspring. The dawning view is that we can pass on the physical and biological effects of our good or bad habits and even the mental states acquired during our lives.

This is a stark change from the theory of evolution through natural selection. Heritable epigenetics is not a slow, thousand-year process. These changes can happen in minutes. A random hit to the head by an enraged lover. A sick, sexually abusive parent. Breathing in toxic fumes. Coming to God in religious ecstasy. All can change us, and possibly change our children as a consequence.

There is not a lick of evidence for any of that!

And there’s this:

. . . It has long been “truth” that the epigenome (the complement of chemicals that modify the expression and function of the organism’s genes, such as the methyl molecules that can glom onto specific genes during the life of the organism due to some environmental change) of the parent is reprogrammed (all epigenetic traces removed) twice: once during the formation of the gamete itself (the unfertilized egg, or a sperm waiting around to fertilize an egg) and secondly at conception. Erase and erase again. But now experiments definitively show that some of the chemicals added during the life of an organism do leave information in such a way that the offspring has [sic] their genes quickly modified in the same way that the parents did. The same places on the long DNA molecules of the newly born (or even the “not-yet” born) get the same epigenetic add-ons that one or both of the parents had. This is not supposed to happen. The revolution is the realization that it does. It happened to the nautilus. And it happens to you and me.

That is a gross exaggeration, and greatly misleading. If you want to see a good consideration and critique of the purported evidence for transgenerational epigenetic inheritance in humans, read this 2018 Wiring the Brain website post (click on screenshot) by Kevin Mitchell (note: he considers the overblown “Dutch famine” data as well):

Mitchell’s conclusion:

In my opinion, there is no convincing evidence showing transgenerational epigenetic inheritance in humans. But – for all the sociological reasons listed above – I don’t expect we’ll stop hearing about it any time soon.

He’s right on both counts: the evidence is horribly weak, and yet we still keep hearing about “Lamarckian” epigenetic inheritance, this time from Ward. After all, the message “Darwin was right” doesn’t sell books, but, in book publishing, “Darwin was wrong” is the scientific equivalent of “man bites dog”

As it says at the bottom of Ward’s article, these passages are from Lamarck’s Revenge. That doesn’t bode well for the book.

h/t: Nilou

34 Comments

  1. Posted August 26, 2018 at 11:42 am | Permalink

    Good stuff! Exactly why I read the blog.

  2. another fred
    Posted August 26, 2018 at 11:43 am | Permalink

    I admire your patience shown in writing a reasoned critique of BS.

  3. Posted August 26, 2018 at 11:50 am | Permalink

    Giraffes!? That’s a stretch.

    • Filippo
      Posted August 26, 2018 at 3:58 pm | Permalink

      I’d like to hear the author/publisher explain/justify the giraffe cover. Is methylation responsible for the extension of the giraffe neck? Is it responsible for the circuitous path of the recurrent laryngeal nerve?

      • Heather Hastie
        Posted August 26, 2018 at 6:46 pm | Permalink

        Perhaps he accepts Ford Prefect’s claim that he was responsible for the “evolution” of the giraffe’s long neck.

  4. keith
    Posted August 26, 2018 at 11:58 am | Permalink

    Hi, Jerry. I wonder if you’ve seen the recently released special issue of Journal of Heredity on epigenetics.

  5. Historian
    Posted August 26, 2018 at 12:00 pm | Permalink

    On a related evolutionary topic discussed recently, David Quammen has posted an article on the Atlantic site touting his new book. He repeats his argument that “the tree of life is not a true categorical because the history of life just doesn’t resemble a tree.”

    https://www.theatlantic.com/science/archive/2018/08/tangled-tree-species-individuals-evolution/568036/

  6. Larry Smith
    Posted August 26, 2018 at 12:19 pm | Permalink

    Great stuff, thanks!

  7. Mark Sturtevant
    Posted August 26, 2018 at 12:40 pm | Permalink

    I don’t know all details about what DNA is used to identify separate species, but cyt c is a very very slow evolving gene, and so is not a reliable measuring stick for detecting separation between sister species like his nautilus. Heck, cyt c is commonly found to be identical between large groups of species, for cryin’ out loud! It is identical between humans and chimps, for example.

    • Torbjörn Larsson
      Posted August 26, 2018 at 12:46 pm | Permalink

      I did not think about that but I do believe you are correct. So they are weakening their signal by (experimental) design.

      • Raymond Cox
        Posted August 26, 2018 at 1:02 pm | Permalink

        It is the cytochrome c oxidase, not cytochrome c. This is a common gene for “barcoding” animals – used precisely because it is universal and highly conserved. There are better targets if you want to distinguish closely related organisms, for example the spacer regions in the ribosomal RNA operon.

    • Torbjörn Larsson
      Posted August 26, 2018 at 12:52 pm | Permalink

      Speaking of design, an aside:

      Their later population structure analysis use their clustered “populations” (and concatenated sequences) instead of the species populations. If those are wrong, that analysis will be too.

  8. Torbjörn Larsson
    Posted August 26, 2018 at 12:42 pm | Permalink

    Well, ordinarily 16S sequences suffice to tell species diversity.

    That said I will go into Sunday rant mode, meaning I have just browsed the 2016 paper and I will drag in other items, which is not an objective evaluation. But it is a start however tainted.

    rant/ So the Lauren Vandepas et al paper starts out carefully, doing some checks that I usually do not see. But then the paper blow up on me, and I am not sure I can use it. They use dated and poor MUSCLE, they do not seem to state the cluster threshold – it can be in the supplements – and they seem to rely on a bayesian support of less than 0.95 despite using > 1kbp sequences. So while the tree looks odd – cluster geographically – I do not find it very useful. And it certainly does not equal to a claim of identical DNA, which is abstracted by Ward seemingly from the odd tree pattern.

    I guess it is the Templeton connection that does it for me.

    Peter Ward’s work, which incorporates, well, odd, astrobiological ideas, is often referenced by creationists. Famously Ward and Donald Brownlee published the astrobiological Rare Earth idea, which in modern Great Filter form amounts to putting putative barriers for human equivalent life. I am sympathetic to the conclusion based on Gould’s older analysis. I am not sympathetic to a model that allows the modeler to choose factors and their number until he or she arrives at a likelihood he or she feels comfortable with. Coincidentally I believe all the factors Ward and Brownlee used in their book such as Moon stabilizing Earth’s spin axis have later been shown to be likely irrelevant.

    Peter Ward has also authored the Medea hypothesis on mass extinctions, which I think has as little evidence speaking for itself (and some against) as the opposite Gaia hypothesis. /rant

    • Posted August 27, 2018 at 1:59 pm | Permalink

      What is it with the religious/ quasi religious and Lamarckism? Is it some sort of weird continental “will to power” schtick? It baffles me how often people want to need a debunkingof the central dogma. Why?

  9. Mark R.
    Posted August 26, 2018 at 12:58 pm | Permalink

    Coming to God in religious ecstasy…can change us, and possibly change our children as a consequence.

    If I was reading this book and came across the above line, I’d promptly shut the book and grab another. Though I do find it ironic that he lumps the epigenetic effects of religious ecstasy with inhaling toxic fumes.

    Thanks for the concise and convincing critique of another book trying to prove Darwin wrong.

    • Posted August 27, 2018 at 2:00 pm | Permalink

      Ah–I believe you may have answered part of my above qustion. Cheers. That still eaves the secular fascination to be explained though

  10. Diana MacPherson
    Posted August 26, 2018 at 1:01 pm | Permalink

    Thanks to Ward and Templeton, I’m starting to associate negative feelings to one of my favourite cephalopods. 🤬

    • Posted August 26, 2018 at 1:25 pm | Permalink

      Doesn’t cephalopod mean foot in mouth (head)?

  11. ThyroidPlanet
    Posted August 26, 2018 at 2:21 pm | Permalink

    Sub

  12. Ken Pidcock
    Posted August 26, 2018 at 2:35 pm | Permalink

    If you haven’t already, bookmark the Kevin Mitchell piece. It’s an excellent reference to provide to those who are enthralled by the supposed significance of intergenerational epigenetic changes.

  13. Steve Pollard
    Posted August 26, 2018 at 4:06 pm | Permalink

    No informed comment to offer; just to say thanks for this lucid and expert review – and for that of Quammen’s book the other day. There are surely not too many sites where one has daily access to such detailed, serious and clearly-written commentaries on science such as this.

  14. Steve Pollard
    Posted August 26, 2018 at 4:08 pm | Permalink

    Arggh – delete the first ‘such’ in that last sentence!

  15. infiniteimprobabilit
    Posted August 26, 2018 at 9:06 pm | Permalink

    Well, Lamarckism would be a much faster and more efficient mechanism for evolution – if it worked. Too bad it doesn’t.

    (Or maybe it might be too efficient and species would disintegrate into a swarm of subspecies and the whole thing would end up as taxonomic soup? I dunno).

    cr

  16. Posted August 27, 2018 at 1:11 am | Permalink

    The methyl molecules are not physically passed on to the next generation, but the propensity for them to attach in the same places in an entirely new life-form (a next-generation life-form) is.

    This seems to imply that the same physical state can give rise to multiple states, which, if we understand anything at all about physics, is wrong.

    But that’s just how I understand it, and I’ll gladly be corrected.

  17. Daniel Engblom
    Posted August 27, 2018 at 4:13 am | Permalink

    These self-professed revolutionaries out for fame and recognition are a dime a dozen, I remember hearing about the miracles of epigenetics back in the late 90s, but in all honesty biology has always attracted this anti-Darwinian attitude, you take the crazy notion passed around before the neo-darwinian synthesis that Mendel and mutations was somehow completely against Darwin.

  18. bobkillian
    Posted August 27, 2018 at 6:07 am | Permalink

    typo: cepalopods

  19. Leigh Jackson
    Posted August 27, 2018 at 7:30 am | Permalink

    There’s an error is in the subtitle of Peter Ward’s book.

    It outht to be:

    Epigenetics has nothing to tell us about evolution.

    • Leigh Jackson
      Posted August 27, 2018 at 7:43 am | Permalink

      Memo to self: ERROR check no matter how brief my comment!

  20. johzek
    Posted August 27, 2018 at 8:19 am | Permalink

    This is uncomfortably close to the claims of homeopathy. In homeopathy water molecules are supposed to “remember” the presence of other molecules no longer there. Similarly, here it is clamed that DNA molecules can, in effect, do the same thing, that is, “sense” the previous presence of methyl groups.

  21. Posted August 28, 2018 at 12:44 pm | Permalink

    On the number of “nautilus species” – this is a single example! So there’s an overgeneralization, even if this were an example that favoured the “epigenetics revolution” partisans.

  22. Posted October 13, 2018 at 6:21 am | Permalink

    Thank you for this posts. Debunking of the phony “epigenetic” fad is badly needed, and the more of it, the better!


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