September 25

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Epigenetics in Evolution with Dr Eva Jablonka

By heheals

September 25, 2020




Dr. Eva Jablonka discusses the role of epigenetics in evolutionary biology. This short take was shot during a break at Keystone Symposia’s meeting on Environmental Epigenomics and Disease Susceptibility held in March 2011 in Asheville, North Carolina.

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  1. Darwin invented our conception of natural selection and thus Lamarck was discredited. Mendel's followers triumphed and Lysenko was discredited for advocating soft-inheritance. Turns out that Lysenko was actually half correct, even more so then Lamarck: traits can be acquired and passed on just like he argued, but it happens precisely through genetics. Ironic that he ended up arguing against the very thing that would decades later prove him correct!

  2. sorry but it's not that simple. Dr. jablonka does not do justice to the critics of the hypothesis that transgenerational epigenetic variations are a factor in evolution. It is not a simple knee-jerk reaction. There are profound epistemological reasons to deny the explanation. Posting an example:

    "…In any case, the arguments against the hypothesis that acquired characteristics are inherited are instructive and will serve to illustrate several aspects of the tangled relationship between the two great stochastic processes. There are three such arguments, of which only the third is convincing:…
    <snip>
    …The final and, for me, the only convincing criticism is a reductio ad absurdum, an assertion that if Lamarckian inheritance were the rule or even at all common, the whole system of interlocking stochastic processes would come to a halt. I offer this criticism here not only in an attempt (probably futile) to kill a never-guite-dead horse [apparently it hasnt died yet!!!] but also to illustrate the relations between the two stochastic processes. Imagine the following dialogue:
    BIOLOGIST: What exactly is claimed by Lamarckian theory? What do you mean by "the inheritance of acquired characteristics"?
    LAMARCKIAN:That a change in the body induced by environment will be passed on to the offspring.
    BIOLOGIST: Wait a minute, a "change" is to be passed on? What exactly is to be passed from parent to offspring? A "change" is some sort of abstraction, I suppose.
    LAMARCKIAN: An effect of environment, for example, the nuptial pads of the male midwife toad.
    BIOLOGIST: I still don't understand. You surely do not mean that the environment made the nuptial pads.
    LAMARCKIAN: No, of course not. The toad made them.
    BIOLOGIST: Ah, so the toad knew in some sense or had the "potentiality" for growing nuptial pads?
    LAMARCKIAN: Something like that, yes. The toad could make nuptial pads when forced to breed in water.
    BIOLOGIST: Ah, he could adapt himself. Is that right? If he bred on land, in the way normal to his species of toad, he made no nuptial pads. If in water, then he made pads just like all the other sorts of toad. He had an option.
    LAMARCKIAN: But some of the descendants of the toad who made pads in water made pads even on land. That's what I mean by the inheri tance of acquired characters.
    BIOLOGIST: Ah, yes, I see. What was passed on was the loss of an option. The descendants could no longer breed
    normally on land. That's fascinating.
    LAMARCKIAN: You are willfully failing to understand.
    BIOLOGIST: Perhaps. But I still do not understand what is supposedly "passed on" or "inherited." The claimed empirical fact is that the descendants differed from the parent in lacking an option which the parent had. But this is not the passing on of a resemblance, which the word inheritance would suggest. It is the passing on of a differenre. But the "difference" was not there to be passed on. The parent toad, as I understand it, still had his options in good shape.

    And so on.
    The crux of this argument is the logical typing of the genetic message that is supposed to be passed on. It is not good enough to say vaguely that the nuptial pads are passed on, and there is no point in claiming that the potentiality to develop nuptial pads is passed on because that potentiality was characteristic of the parent toad before the experiment began.

    Of course, it is not denied that the animals and to a lesser extent the plants in this world often present the appearance which we might expect in a world in which evolution had proceeded by pathways of Lamarckian inheritance. We shall see that this appearance is inevitable given (a) that wild populations usually (perhaps always) are characterized by heterogeneous (mixed up and diverse) gene pools, (b) that individual animals are capable of somatic changes which are in some way adaptive, and (c) that mutation and the reshuffling of existing genes are random. But this conclusion will follow only after the entropic economics of somatic change has been compared with the entropic economics of achieving the same phenotypic appearance by genetic determination."
    Gregory bateson, "mind and nature, a necessary unity"

    so far there are more questions than answers with dr. jablonka's hypothesis

  3. I have been working on how organisms can set up the context of evolutionary change by epigenetic and plastic responses. Processes such as niche construction, adaptive radiation, species co-interactions, niche shifts and species invasions can favor the recurrence of adaptive epigenetic variants, especially if its the result of what I call evolutionary epigenetics capacitors. My work on the rate of genetic assimilation is groundbreaking in this respect. If there is even just 200 possible canalizing mutations that can assimilate a specific plastic response even at 25% robustness. This can mean that within populations that breed every 2 weeks that produce 15 offspring can assimilate a new envirotype within as little as 20-10 generations

  4. Some witnessing for Terence McKenna's brilliant 'stoned ape theory' sure see what they like and like what they see in this brand theorizing (regardless how it figures in contexts more educated less 'rigorously uncritical'). "[McKenna's] theory is not unscientific bogus. There is a good literature, see Jablonka & Lamb. I wrote a review about FOOD OF THE GODS & explained why Mckenna's idea is not naive Lamarkism." I'd love for Jablonka address how well her theorizing lends to brilliant stuff like "stoned ape" schmeory – I mean, theory. You can't make this stuff up… http://www.amazon.com/review/R60P5REUXQ8JQ/ref=cm_cd_pg_pg2?ie=UTF8&asin=0553371304&cdForum=Fx3NTNB0HDOLTZ9&cdPage=2&cdThread=Tx2FLLHFP6VDNKI&store=books#wasThisHelpful

  5. Hmm we do need to systematically study the role of epigenetics in evolution. Even if some traits are transmitted to an offspring, if the offspring is not able carry it forward and propagate it to the second generation, and to add more onto it, it would not have evolutionary impact.

  6. A monotheistic, rational god that created the universe from outside space-time, made man in his own image, allowed spiritual evolution ,mother seeking of truth, the questioning of earthly leaders, the equality of those from different genders, races and nations., and perched love, peace , hood news and hope to all. Which religion do you think I mean?

  7. Organisms evolve and it fascinates me. What dismays me is blind adherence to neo-Darwinism and the faith of many evolutionary biologists in a godless irrational universe which ultimately would kill science.

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