Again with this Lamarck guy

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Cross-posted from Reaction Norm

ResearchBlogging.orgHere he is “late in life.”  Everyone already thinks he’s wrong wrong WRONG. We know him now as the Wrongest Biologist Ever. When we say “Lamarckian” we mean the idea that acquired characteristics can be inherited. I can almost hear him crying from the grave, “I produced a lifetime of ideas on all kinds of stuff, yet ‘Lamarckian’ will always mean just that one thing.” No wonder he looks a little shifty and bitter. Well, most of his other stuff was wrong too, but it was like 1800 and he was trying to convince people that species evolved without divine intervention! Pardon him for not getting the details right.

But he was wrong. Except when he was right. “Lamarckian” phenomena aren’t all that uncommon, especially in prokaryotes. Of course, he was still wrong because he didn’t know about any of the phenomena that he was right about—he was basing his ideas on types of evolution that simply aren’t “Lamarckian.” It’s fashionable these days to defend Lamarck, and it’s always been fashionable to dismiss things like genetic assimilation or the Baldwin Effect as “Lamarckian,”  which they aren’t. Someday, perhaps someone will describe some epigenetic phenomenon in which an environmental variable specifically alters a locus in the germ line (Weissman stirs in his grave) such that the inheritors of that altered locus are better adapted to that environment. But no one is holding their breath.

But wait! What’s this in today’s issue of Current Biology?

Stable inheritance of an acquired behavior in Caenorhabditis elegans

Huh. First, it’s a single author paper, which is sometimes a crackpot alert. But Current Biology is respectable. And the author, Jean-Jacques Remy is from a respectable lab. And it’s a really simple paper with no mechanism, just getting the phenomenon itself out there. So here it is.

imageC. elegans imprints on odors it experiences as young worm. If they are exposed to benzaldehyde as larvae, they show a greater level of attraction to benzaldehyde as adults. This involves a couple neurons. Now, Remy is claiming that if a worm is imprinted, its offspring (F1) show the same enhanced attraction to benzaldehyde, even though it’s never smelled it before. However, the grandkids (F2) do not show the imprinting effect.

If however you imprint multiple generations (more than 4), the behavioral switch becomes stable, and is inherited for multiple generations (at least up to 40 generations). The behavior is odor-specific and is also discrete—there is an “imprinted” state and a “naïve” state, with nothing in between, as you would expect if there was something being diluted over time.

Note, this is not genetic assimilation for two reasons: 1. There is no selection for the behavior, 2. This is all done in an isogenic strain—there is no genetic variation in the population.

That’s all there is to it—no experiments to get at mechanism. So we’re left with a sort of “ok, you need to convince me it’s real” kind of feeling. There is a lot they could be doing here, and probably are. For example, testing the requirement for chromatin modifying enzymes, or microarray analysis of imprinted and unimprinted lines. The fact that they published this as just the behavioral inheritance observation makes me think there is competition and Remy wants priority. Anyway, it will be exciting to see how this plays out.

Anyone see any obvious problems with the data (such as it is)?

Remy, J. (2010). Stable inheritance of an acquired behavior in Caenorhabditis elegans Current Biology, 20 (20) DOI: 10.1016/j.cub.2010.08.013

5 Comments

  1. Yawn. Look up “epigenetics” in wikipedia. a host of environmental influences can be passed on.

    No biggie.

    Then, there’s http://www.starlarvae.org.

    Now THAT’S news!

  2. I don’t see any problem with the data, provided that they are described accurately. If real, studying the mechanism should be fascinating. By now Remy should know whether the switch is truly stable or if it goes away after >100 generations. That’s the key. And, of course, if it is stable how it behaves in crosses. In any case this sort of “additive epigenetics” is certainly interesting. I haven’t seen any examples of such.

  3. The author sounds suspiciously *French*. For reasons of national pride, neo-Lamarckism had holdouts among French biologists long after it had (almost) died out elsewhere.

    ‘Lamarckist’ findings keep cropping up from time to time, but usually they fail on attempts to replicate them. I remember that some time ago there was great excitement when flatworms could apparently ‘learn’ by being fed on the mashed-up bodies of other flatworms that had been habituated on some task. Ingenious hypotheses were put forward to explain it. Of course, the whole thing was a crock.

  4. Cricket Jones
    dkydd1@gmail.com

    Great link to the examples of ‘Lamarckean and quasi-Lamarc thingys (really). If naysayers like DavidB want to demolish the credibility of Lamarckean hypotheses, they will have to address the empirical data that you provided instead of ad hominum mud slinging. “It’s a French problem, no problem” won’t cut it.

    Moving right along, I suggest that in contrast to your hyperlinks to unreliable Wikipedia sites for defs of crucial concepts like the Baldwin Effect or genetic assimilation, it seems to me a more helpful link would be to specific articles from solid-impact scientific journals. gene expression aims to be a respectable, veridical mouthpiece for everythg genery. no? kinda. so you owe it to yourselves and us to hyperlink trustworthy sources.

  5. There is no point in ‘addressing empirical data’ if the empirical data are false. When ‘data’ are a priori improbable (like finding birdshit in a cuckoo clock), the first step is to see if they can be independently replicated. Nine times out of ten in the past ‘Lamarckist’ claims have failed the replication test, from Brown-Sequard in the 1880s to Steele in the 1990s. In the light of a long history of false, fraudulent, and misinterpreted data (like McDougall’s tests on rats in the 1930s), a sceptic is entitled simply to ignore any new claims until they have been independently replicated several times.

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