1. hemidactylus says

    Thanks Mierze. That was an awesome video and tangentially linked to the hype over the extended evolutionary synthesis as Jablonka and Lamb are a part of that movement and promote epigenetic Lamarckism (so-called). Lamarck didn’t invent the idea. In their contribution “Transgenerational Epigenetic Inheritance” in Pigliucci and Muller’s _Evolution: the Extended Synthesis_ they review a bunch of interesting stuff that seems at best transient as you say. One thing that struck me that dovetails with the hunger studies was an aside on womb effects. They say: ““For humans and rats, there is a positive correlation between environmentally influenced maternal size and offspring size: small mothers have small wombs, with reduced uterine perfusion, and this leads to small offspring.” I would wonder if well nourished human mothers give birth to daughters who will have greater capacity to have larger daughters and so on to a genetically constrained limit, but maybe making childbirth riskier. And as an unimportant side effect males would get larger too. There may be similar trends with nutrition and IQ over generational time or that secular effect thingie. But this isn’t evolution.

    Your germline segregation portrayal was great, but didn’t your fellow balcony muppet Waldorf Moran warn us about generalizing based on early germline segregators? This bottleneck would not apply to protists. Central dogma is more important but perhaps irrelevant to transmission of epigenetic marks

    I am not very interested in that sort of epigenetics, but have long been captivated by Piaget’s notion that behavior leads evolution. He was a biologically well informed psychologist and very aware of the Baldwin effect and Waddington’s genetic assimilation. You seemed to allude to such things with Dobzhansky’s selected reaction norms. Piaget even speculated about reverse transcription. His ideas were kinda fluffy I recall.

    I wonder if populations exhibiting variation in behavior such as lobe finned fish that tended to struggle toward dry land more often would set a selective regime that co-opted lobes into tetrapod limbs.

    Or less behaviorally would teratogens or environmental stressors produce Goldschmidt’s phenocopies that happen fortuitously to be better adapted and genetics eventually codifies the change.

    A better example of plastic behavior via learning impacting evolution would be lactase persistence amongst milk drinking cultures. Blessed are the cheesemakers. I think the EES crowd rolls this one into niche construction, which is a fascinating topic covered by John Odling-Smee in the same book cited above. He talks a bit about allelopathy, which is a known phenomenon where organisms put out noxious chemicals to reduce competition (similar to political attack ads).

    The most fascinating but probably wrong work on molecular Lamarckian processes was Ed Steele’s arguments in Lamarck’s Signature. He thought retrovectors could pick up on the signal generated by the genetic variations in immunocytes responsible for adaptive immunity and reverse transcribe it into germline cells, violating Weismann’s barrier but not central dogma of unidirectional flow from nucleic acids to peptides (cue Waldorf). I couldn’t get past the mapping problem between adaptive immunity in specific immunocytes and germline changes, but it made more sense than the transmitted methylation patterns Jablonka and Lamb push. And immunocytes shuffling and hypermutation genes was learning well worth struggling with an immunology course. Awesome sauce.

  2. nobonobo says

    #1 gecko, the contrast between PZ’s video and your comment made me laugh at how much research was necessary to follow yours. Different target readers, heh.

  3. chris61 says

    Maybe the next time you talk about DNA methylation you won’t say that it’s methylated on the backbone when it’s actually methylated on the bases (i.e. cytosines in particular).

  4. DonDueed says

    Tangential point of interest: the mother of actress Audrey Hepburn was among those who experienced the Dutch Hunger Winter. She was pregnant with Audrey at the time.

    I’m not sure what stage of the pregnancy was affected, but Audrey didn’t seem to suffer from any tendency toward obesity.

  5. ambera says

    I have a question that I don’t know where else to ask. A chicken vs egg discussion has popped up and turned into a discussion about evolution. Most of the folks in the discussion are saying egg came first: Nonchicken laid an egg with genetic mutations that resulted in chicken. I’ve been saying that’s wrong. The offspring is always the same species as the parents, and the nonchicken to chicken transition doesn’t have a single generation line. Now they’re quoting Tyson, Dawkins, and Hawking at me saying they all state scientifically the egg came first (my own position is that the question directly has no answer as it is inherently circular, but if you must interpret it in a way to come up with an answer, I went with egg = any egg and chicken = living thing. Therefore chicken came first since eggs are a later “invention”). How sound is my understanding of evolution here?

  6. Porivil Sorrens says

    There were egg-laying things in existence long before there were things remotely resembling chickens.

  7. ambera says


    Reread what I said. I used chicken as a metaphor for mature living thing. Living things reproduced through division before there were eggs.

  8. empty says

    Lamarck seems to get all the blame for this but perhaps a more appropriate recipient of the blame would be Darwin with his wonderfully loony theory of pangenesis and gemmules. I think the name “gene” was used specifically as a counterpoint (?) to pangenesis. I remember reading about it in one of the later editions of On the Origin of Species but Wikipedia is telling me my (aged) memory is incorrect. It was actually proposed by Darwin in The Variations of Animals and Plants Under Domestication.

  9. Porivil Sorrens says

    Yeah, I just think your interpretation is a silly myopic view that dodges the point of the question.

  10. says

    Excellent video, PZ. You emphasized the weakness of the effects and the problem of confirmation bias. When I encounter people touting the epigenetics-revolution argument, I try to get them to understand that epigenetic changes have only been shown to persist for a few organism generations (in the roundworm Caenorhadbitis elegans, a bit longer). If a lineage of, say, apes, develops a different pattern of methylation, that will be expected to revert quickly and not to predict that the pattern of methylation will still be around a million years later.

    I also try to get them to understand that when an environmental effect changes the methylation pattern, there is no reason to believe that the effect is adaptive. When the Dutch famine induces a rise in schizophrenia, that does not seem to cause any ability to resist famine. Like genetic mutations, changes of epigenetic patterns will be random with respect to their effect on fitness.

    In addition to your fine video, here are some takedowns of epigenetic-revolution-in-evolution hype by Jerry Coyne:

  11. ambera says


    Do continue. I’m sure you have a well considered reason behind your out of no where insulting response.

  12. hemidactylus says

    @7- PZ
    Thanks for the suggestion, but I am not much into video chat and would feel out my league. I learned most of my biology in late 90s and though I am trying to rejuvenate some synaptic connections with relevant reading, at this point I am pretty much mailing it in. It would be cool to watch you and another professional such as Felsenstein chat it up. Maybe invite Moran so he can plug the book he is working on. How’s your book coming along?

  13. Porivil Sorrens says

    There’s nothing more to say. It’s a simple question that you’ve twisted into a weird myopic version to avoid the common, simple answer.

    The way the question is actually meant, egg laying beings predate chickens.

  14. ambera says

    First of all, that’s not even the question I was asking. I was asking if my understanding of speciation – that it does not occur between parent and offspring but across generations and involves the entire breeding population was correct. As for chickens and eggs, if you go back through the generations and point out egg laying animals predate chickens, what stops you from going back further to point out non egg laying animals predate eggs?

  15. Porivil Sorrens says

    Nothing stops you from pointing that out. Unfortunately, the question specifies chickens, which are a modern, egg-laying species.

  16. ambera says

    The question is also about chicken eggs. It’s implied. Which came first, the chicken or the chicken egg. It’s meant to be a thought exercise about cycles. The moment you start talking about non chicken eggs you’ve gone beyond the limits of the thought experiment and there’s nothing stopping you talking about non chickens too.

  17. hemidactylus says

    We’re not seriously arguing about chickens versus eggs are we? And feathers are ruffled? Oh my.

    Chickens are amniotes. The so called cleidoic egg laid by these amniotes predates the advent of avian dinos. So the ancestors of chickens laid eggs. I am mostly ignorant of bird phylogeny but as with any grouping it is a hard call to make when that group or evolving population achieved chickenhood.

  18. ambera says

    It was never my plan to argue about chickens and their eggs but somebody took offense at the part of my post that wasn’t actually relevant to my question.

  19. hemidactylus says

    @11- empty
    Darwin had his speculative notion of heredity. German biologist Ernst Haeckel had a similar idea except that it was based on vibration:

    “Haeckel’s term for: a former theory of reproduction in which it was supposed to be caused by regular vibrations of plastidules.”

    I won’t knock Haeckel for his bold try, but why do all the current goofy fringe ideas all seem to rely on tapping into vibrations out there? Morphic resonance, water memory, law of attraction (the Secret)…Strange.

  20. billyjoe says

    I think you need some background knowledge of epigenetics to fully understand the argument contained in the video, including what Jablonka, Lamb, Shapiro, and Pigliucci (surprise!) are falsely claiming regarding the merits of EES. The video then clearly explains why they are wrong. There really is no other conclusion based on the evidence to date. There must be a change in the genome for there to be long term evolutionary adaptation. The transgenerational effects of epigentics cannot be anything other than temporary.

  21. billyjoe says

    Nerd alert!

    On chickens and eggs:

    If it’s chickens and chicken eggs, then maybe chicken eggs came first. Except that there is no point in time where you could say “this is the first chicken”. If you could then, yes, the chicken egg came first, because the first chicken must have come from a chicken egg (otherwise that egg would not have produced a chicken). But you can never say “this is the first chicken” either in real time (because species are only recognizable in retrospect) or in retrospect (because it is a gradual process in which at one time there is a non-chicken and sometime later there is a chicken. Analogy: you were once a child and now you are an adult, but there was no point in time – occurring either in real time or retrospectively – when you transitioned from childhood to adulthood). The best you can say, it that it both tracked parallel paths, or some such thing. Or it’s unanswerable.

    If it’s chicken and eggs (unspecified), then the answer is clearly eggs, because eggs (of any type) pre-dated chickens.

  22. rietpluim says

    The first chicken is the oldest ancestor of present-day chicken not being the ancestor of any other species.