Over at the Guardian, Oliver Burkeman, a writer who apparently knows nothing about evolution, has a long piece called “Why everything you’ve been told about evolution is wrong.” Everything? Really? Burkeman seems to have a beef with Richard Dawkins, and seems to take delight in how the new “evolution revolution” would vex him:
What if Darwin’s theory of evolution – or, at least, Darwin’s theory of evolution as most of us learned it at school and believe we understand it – is, in crucial respects, not entirely accurate? Such talk, naturally, is liable to drive evolutionary biologists into a rage, or, in the case of Richard Dawkins, into even more of a rage than usual.
Well, maybe Burkeman’s insistence that popular notions about evolution are all wrong is just journalistic puffery. So what is the new finding that overthrows Darwinism?
Epigenetics.
There are several definitions of “epigenetics” (it once meant simply “development”), but Burkeman uses the term in its more modern sense as “inheritance not based on coding changes in the DNA.” Burkeman cites a couple of recent studies in which nongenetic, developmentally caused changes in an organism (like alterations in physiology due to starvation) can be passed on to one or two generations of its descendants. The offspring of stressed Swedish chickens, for example, have difficulty navigating mazes. He gives another two-generation example of epigenesis from humans.
This thin evidence, apparently, is why modern evolutionary theory is wrong. And so Burkeman gets in another slap at not only Dawkins, but Daniel Dennett:
As years of bestselling books by Dawkins, Daniel Dennett and others have seeped into the culture, we’ve come to understand that the awesome power of natural selection – frequently referred to as the best idea in the history of science – lies in the sheer elegance of the way such simple principles have generated the unbelievable complexities of life. From two elementary notions – random mutation, and the filtering power of the environment – have emerged, over millennia, such marvels as eyes, the wings of birds and the human brain.
It not be immediately obvious why this has such profound implications for evolution. In the way it’s generally understood, the whole point of natural selection – the so-called “modern synthesis” of Darwin’s theories with subsequent discoveries about genes – is its beautiful, breathtaking, devastating simplicity. In each generation, genes cause random mutations, making offspring subtly different from their parents; those mutations that enhance an organism’s abilities to thrive and reproduce in its own particular environment will tend to spread through populations, while those that make successful breeding less likely will eventually peter out. Yet epigenetics suggests this isn’t the whole story.
All I can say to this is: “Profound implications my tuchus!” There are a handful of examples showing that environmentally-induced changes can be passed from one generation to the next. In nearly all of these examples, the changes disappear after one or two generations, so they couldn’t effect permanent evolutionary change. The proponents of epigenesis as an important factor in evolution, like Eva Jablonka and Marion Lamb, always wind up talking about the same tired old examples, like cases of coat color change in mice and flower pattern in toadflax. I am not aware of a single case in which an adaptive change in an organism—or any change that has been fixed in a species—rests on inheritance that is not based on changes in the DNA. (For a refutation of the pro-epigenesis arguments that Jablonka and Lamb make in their 2005 book, see Haig [2007].)
Moreover, some examples of “nongenetic” inheritance that do have adaptive significance, such as differential methylation of paternal versus maternal chromosomes, ultimately rest on changes in DNA that promote that differential methylation. And this “inheritance” lasts only one generation, for the methylation profile is reset in each sex every generation.
In contrast to the very few cases of one- or two-generation inheritance that cause nonadaptive changes in the phenotype stands the very, very large number of studies in which inherited changes within and among species map to the DNA. These include every case of evolutionary response to artificial or human-generated selection, adaptive changes within species (e.g., spiny-ness in sticklebacks), and differences among species in both morphology (e.g., the color differences in fruit flies I study) and reproductive barriers (the many mapping studies of “hybrid sterility” and “hybrid inviability” genes). Burkeman, of course, doesn’t mention these cases: it would ruin his nice story.
If we look just at studies of the inheritance of organismal changes that have evolved over time (and many of these would have detected profound epigenetic effects), the score would be something like this: DNA 757, Epigenesis 0. (I’m just making these numbers up, of course, to make a point.) If we look at all “inherited changes”, regardless of their evolutionary importance, we would have a handful of epigenetic changes versus literally thousands of DNA-based changes. So how can Burkeman say that epigenesis will profoundly revise our view of evolution?
Now I’m not saying that epigenesis was completely unimportant in evolution. Prions (cases in protein shape that don’t reflect changes in protein sequence), for example, could be considered cases of epigenetic inheritance, and might have played a role in the evolution of some species. What I am saying is that there is virtually no evidence that epigenetic inheritance has been important in evolution, and that the phenomenon seems, at this point, seems too infrequent to warrant rethinking the tenets of neo-Darwinism.
Burkeman notes that epigenetic inheritance appears to refute one of the prime tenets of evolutionary psychology: the idea that DNA-based changes in human behavior evolved by natural selection:
And now, if epigenetics and other developments are coming to suggest that environment can alter heredity, the very terms of the debate – of nature versus nurture – suddenly become shaky. It’s not even a matter of settling on a compromise, a “mixture” of nature and nurture. Rather, the concepts of “nature” and “nurture” seem to be growing meaningless. What does “nature” even mean if you can nurture the nature of your descendants?
Now, I’ve been a critic of the excesses of some evolutionary psychologists, but it’s simply insane to dismiss that field—and, by extension, the entire field of behavior genetics—because there is some thin evidence for inheritance of acquired traits.
Inevitably, Burkeman got wind of Jerry Fodor and Massimo Piattelli-Palmarini’s new book, What Darwin Got Wrong, a profoundly misguided critique of natural selection. Burkeman notes, correctly, that the book has met with fierce opposition from philosophers and biologists, but insists that it still has value:
It would be jawdroppingly surprising, to say the least, were Fodor to be right. A safer, if mealy-mouthed, conclusion to draw is that his work acts as an important warning to those of us who think we understand natural selection. It’s probably not a bankrupt concept, as Fodor claims. But nor should laypeople assume that it’s self-evidently simple and exhaustively true.
Probably not a bankrupt concept? Not self-evidently simple? (It is—that’s one of its beauties!) Not exhaustively true? (What does that mean? Is there any explanation for adaptation other than natural selection? Fodor has certainly never given one.)
Burkeman’s article represents the most self-serving, lazy, overblown, and irresponsible strain of science journalism. He lays out strong charges against modern evolutionary biology, and then doesn’t bother to consult a single expert to see if those charges stick. He touts epigenesis to the skies, but doesn’t bother to find out whether its proponents may have exaggerated its evolutionary importance. (That wouldn’t have required much digging!) Burkeman apparently lacks the ability to adjudicate claims and controversies in biology. Granted, we don’t expect all journalists to be able to do this, but if you don’t know what you’re talking about, you ask the experts.
Finally, Burkeman is not even a science writer—he’s a “features” writer. What business does he have telling the public that everything they know about evolution is wrong? He appears to be motivated far more by an animus against Richard Dawkins, and a desire to write catchy and sensationalistic science journalism, than by a desire to get the facts.
Burkeman is an ignorant fool. He belongs not at the Guardian but on page 3 of the Sun, where he can exaggerate and hyperventilate to his heart’s content.
UPDATE: The Guardian is backpedaling: there’s been a rebuttal piece posted on the Guardian’s own Comment is Free site (for the link, see Matthew Cobb’s comment #15 on this post).
____________________
Jablonka E, and M. Lamb M. 2005. Evolution in four dimensions: genetic, epigenetic, behavioral and symbolic variation in the history of life. MIT Press, Cambridge, MA
Haig, D. 2007. Weissman Rules! OK? Epigenetics and the Lamarckian temptation. Biology & Philosophy 22:415-428
I am impressed. I read Burkeman’s article at lunchtime in England and think to myself “Jerry Coyne will have something to say about this”. I go round to this website and – whoa! – there’s a robust criticism already posted. At 6:15am in Chicago.
Do you have some sort of alarm system in your house that wakes you up whenever biological nonsense is published anywhere in the world?
I agree – that was an impressively quick evisceration of the Guardian piece, professor Coyne!
““Why everything you’ve been told about evolution is wrong.“ ”
You know, there might be some unintended truth here:
1. Most of us “learn” evolution from outside the science classroom. I know that part of my lay-education on the subject goes something like this:
a. Read an article that you are quoting.
b. Be inspired to read a competent lay-book on the subject (e. g. WEIT, TGSOE, Futuyma’s books) and find out that what was said in part “a” was wrong. 🙂
2. I know that when evolution was first presented to me, it was taught very poorly. We were told “humans evolved” and shown a poster showing linear “monkey to human” transition. That was it. Hence I didn’t believe it when I was a kid. I didn’t know WHY a species would branch off.
Hearing “natural selection” was akin to putting on my glasses for the first time.
I hear you – my travel was something similar.
[I even got a biology stipend of sorts, a book on Linnaeus, while I can’t remember anything about mechanisms discussed. (It only happened because no one else went up to the plate to pitch in biology class – my hearth was in physics already then.)
Nowadays I find that book choice of my gymnasium (secondary school) oddly appropriate.]
There seems to be more and more of this BS going on since that dreadful cover “Darwin Was Wrong” was published in the New Scientist.
There’s one good thing coming out of it for me, though: it kinda proves that Evolution is standing up to all these dumbass attacks against it from ignorant and bloviating idiots. Every time they bring up “evidence” that tries to crash Evolution, it doesn’t crash it at all.
It also shows that science actually works: people can question all they like with evidence without screaming “censorship” as the Creationists do. Of course, you’ll never convince the Creationists of anything anyway, but maybe, in time, it will convince some of the more moderate people if we use these sorts of things as examples in certain ways.
BTW, I totally love your blog and read your entries every morning. =)
Summer Seale.
This specious overextending of epigenetic wonderlust is sweeping several predominate philosophy departments in hopes of creating a “new post-modern evolutionary paradigm.”
It gives non-specialists the bravado to speculate with quixotic temerity. You hit the nail: self-serving and lazy.
Burkeman: “In the way it’s generally understood, the whole point of natural selection – the so-called “modern synthesis” of Darwin’s theories with subsequent discoveries about genes – is its beautiful, breathtaking, devastating simplicity.”
Nice strawman.
The point of natural selection is its simplicity? What the hell does that even mean? Forget the science, that’s just muddled writing.
Why do people always seem to think that Dawkins is an angry person?
Because he makes THEM angry and they project their anger onto him.
It seems like there is nothing that riles the religious more than someone who in a calm, but assertive manner can explain that they are wrong, and have ample proof to show why.
As one of these calm and assertive ones, Richard Dawkins comes out on top, so the xians only hear that their cherished belief can be proven to be rubbish, and only superstition. And that they consider being very aggressive, poor sods.
The basics of evolution through inheritance with variation and natural selection is indeed a very simple idea. But this is not the same as saying that the way natural selection actually plays out in real life is simple. People like Burkeman and Fodor and Piattelli-Palmarini seem to think they offer some profound insight when they discover something complex and go “Aha! Darwin was wrong because it’s not that simple”. In the mean time, real biologists will face-palm and say “we know it’s not that simple, we’re the ones who figured that out in the first place, you know”.
It’s kinda like someone finding out that learning to play chess well is difficult, and therefore concludes that the observation that chess is based on just a few simple rules must be false.
“Burkeman is an ignorant fool. He belongs not at the Guardian but on page 3 of the Sun, where he can exaggerate and hyperventilate to his heart’s content.”
But then where would they put the hot topless women?!!!
He’d write the CAPTIONS! “The lovely Jane, hailing from Penzance, revises every notion we have of what a woman is.”
Oh, that was quite good.
!!!!!
(laughed out so loud I almost choked coughing, courtesy of my pneumonia)
Me too, and I don’t even have pneumonia (poor you, get better soon).
i shouldnt have read this while tooth brushing… ;D
My condolences on only having one tooth.
please! no condolences! its special! its shiny! its my only one! my preeeeecious!
p.s. tOOth brushing is the act of cleaning/brushing your tEEth with a (hopefully pink and sparkly)toothbrush-otherwise my english teacher in 7th grade (here in germany) played a reaaaalllly mean trick on me 🙁
I think you are safe.
It’s when you start teeth brushing that your oral (and vocabulary) hygiene goes through something best left in page 3 of the Sun.
(And yes, poor Occam!)
Your teacher was correct. Just as one refers to window cleaning, not windows cleaning.
heh- okay i was probably partly lying. i think i learned how to brush my teeth in kindergarten. my first kindergarten was in greenwich,connecticut, so i didnt learn the phrase in a german school.though: im born in germany and lived here for the better part of my childhood, so i hope it wasnt that much of a lie. 😛
Here is Eva Jablonka’s opinion on (epi)genetics.
“Epigenetics is a term that includes all the processes underlying developmental flexibility and stability, and epigenetic inheritance is part of this. Epigenetic inheritance is the transmission of developmental variations that have nothing to do with changes in the DNA base sequences. In its broad sense, it covers the transmission of any differences that do not depend on gene differences, so it encompasses the cultural inheritance of different religious beliefs in humans and song dialects in birds. It even includes the developmental legacies that a young mammal may receive from its mother through her placenta or milk—transmitted antibodies, for example, or chemical traces that tell the youngsters what the mother has been eating and, therefore, what they should eat.”
This elevates epigenetics as an either or to genetic inheritance, which is simply overplaying your hand.
Wow, so culture is just a subset of epigentic inheritance.
It never ceases to astound me how supposedly well educated people can fail to understand that life is DNA. No matter how convoluted the chain of events, the structure of DNA is ultimately the only thing replicated.
That and the working cell machinery which is also inherited in an unbroken chain although replenished by DNA. (So I wouldn’t call it epigenetics albeit the function isn’t developed (much).) Our own “warm little pond” that we still need to lug around – ask viruses.
Every single bit of a cell must be reconstructible from DNA for continued mitosis to be possible, even though there’s an obvious bootstrapping problem.
Craig Venter’s people did an experiment where they removed all DNA from one bacterium and inserted the genome from another. Over time, the bacterium was changed to reflect the species characteristics of the donor DNA.
There may very well be some cellular structures that need continuity. That is, they could not be reproduced from scratch by the current cell DNA. But such structures would still not qualify as replicators. They would more appropriately be thought of as necessary parts of the environment that the existing bits of DNA depend upon, albeit ones which are continually extended and modified.
An analogy at the organismal level would be with caddis fly larva, which are quite incapable of creating rocks and flotsam, but which depend on those bits to construct their little houses. DNA might likewise depend on some level of pre-existing structure in, say, the cell wall of a bacterium.
What a fucking idiot. Jesus fucking christ.
Jesus was Christ, so he obviously can’t fuck himself. (thoughtful pause) No, wait, he actually could.
What an unfortunate article from one of my favorite periodicals. Too bad. According to his definition, all culture is epigenetic, but recognizing this does not entail that evolution is wrong; in fact many models of cultural change use genetic and non-genetic components (such as the models proposed by Laland).
As Prof. Coyne notes in his critique, semantically-speaking it would seem that lots of inheritance is apparently “epigenetic” since many of our inherited traits represent fixed factors that involve no “coding changes in the DNA” (e.g., an 18S RNA sequence between parent and offspring probably has no coding changes but is still inherited).
Fair criticism. Although Burkeman’s comments about fodor at the end were clearly the result of some thought on his part, and he did say he was “probably wrong”
He also mentioned that the effects of epigenetic inheritance were temporary and might not be too important to evolution. Perhaps failing to notice that this made his whole article redundant.
…sorry, re: above post the last “he” in the fist sentence refers to Fodor not Burkeman
Whenever I see a title or a statement along the lines of “Everything you know about X [be it evolution, cancer, a historical incident, etc.] is wrong,” I know that I’m about to be treated to a heapin’ helpin’ of bloviating bullshit.
That reminds me, I must get over and see if “Everything I know about my Friday dose of woo is wrong!”
There’s been a riposte by Adam Rutherford at Teh Guardian
http://www.guardian.co.uk/commentisfree/2010/mar/19/darwin-evolutionary-science-media-coverage
And the mods on the discussion of the original article are bleating that it was read by two science writers “with PhDs”. Name and shame!
If I remember correctly yesterday Burkeman contributed an article to The Guardian about buying his underpants second-hand from a charity shop. At least he is qualified to comment on that subject. Perhaps Dr. Coyne could give us his views on wearing someone’s cast off undercrackers?
Perhaps Burkeman’s ability to get his knickers in a twist without a moment’s hesitation stems in part from having pre-twisted knickers.
How many read the Guardian (Guardian of what, actually?) before this ‘series’, say, in a regular schedule? (well?). Occam’s razor says that many have fallen into the Nepenthes pitcher and unlike the shrews, flush the toilet.
I usually buy it to read on Saturday and its companion The Observer on Sunday. And I flip through its headlines most days during the week.
It’s usually pretty good, despite the lapses that we’re ridiculing.
The Independent is also quite good.
Ahhh, but you live in urbanic landscpaes: access to written press…sometimes I even miss Barnes & Noble…
‘Occam’s razor says that many have fallen into the Nepenthes pitcher’
Now I’m supposed to have a talking razor?
And I thought the gabby Gillette was just a side-effect of too much ephedrine in the bronchospasmolytic…
Am reading Observer on-line, but was particularly diligent when Terry Jones (from Monty Python) made contributions.
His ridiculing of GWB and the US attack on Iraq was scathing and amusing in its warped logic.
Maybe someone can explain this to me… but it seems to me that even if Jablonka and Lamb and other proponents of epigenetics as a dominant force in evolution were correct, it still would not so much be a refutation of the modern synthesis, but a building-upon of it?
Yes, you’re right, of course. Indeed, the modern synthesis was forged before we knew anything about DNA, and that synthesis relies just on the fact of “inheritance,” not “DNA-based inheritance.” This is something that many of the Epigenetics Fan Club forget when saying that it overturns neoDarwinism!
Has any scientist-well, evobiologist- claimed that epigenetics overturns neoDarwinism? Why the neo, anyways? But i may be wrong.
I meant to say that I dont know anyone who has. My keyboard hasnt taken her medicine yet
From a New Scientist article on epigenetics:
What does Dawkins himself think? “The ‘transgenerational’ effects now being described are mildly interesting, but they cast no doubt whatsoever on the theory of the selfish gene,” he says. He suggests, though, that the word “gene” should be replaced with “replicator”. This selfish replicator, acting as the unit of selection, does not have to be a gene, but it does have to be replicated accurately, the occasional mutation aside. “Whether [epigenetic marks] will eventually be deemed to qualify as ‘selfish replicators’ will depend upon whether they are genuinely high-fidelity replicators with the capacity to go on for ever. This is important because otherwise there will be no interesting differences between those that are successful in natural selection and those that are not.” If all the effects fade out within the first few generations, they cannot be said to be positively selected, Dawkins points out.
I wholly endorse his view.
The selfish replicator…..it had been a while before it crept out again…..
The second blockquote has the paragraphs reversed. The article goes “It might [you missed this word, too] not be immediately obvious why … As years of bestselling books by Dawkins, Daniel Dennett and others … Yet epigenetics suggests this isn’t the whole story.”
Anyone know of reviews of David Shenk’s book, The Genius in All of Us?
Wait, but I thought that the evil evolutionists were actively supressing all anti-evolution research. After all, that is why the Discovery Institute has to do all of its earth-shattering research in secret laboratories at undisclosed locations by anonymous scientists. Why are these people doing epigenetics research still alive, not to mention still having jobs?
Why don’t we just cut the bullshit and turn our discussion toward what is the REAL REASON for why seemingly highly intelligent people like Jerry Fodor and David Shenk have such a strong desire to discredit Darwin’s theory of evolution and to deny the power and agency of DNA-based genetic differences.
The answer is that Jerry Fodor and David Shenk probably deeply believe in the moral rectitude of liberal Boasian equalitarianism. Darwin’s theory of evolution and especially the growing acknowlegement of the immense power of genes to influence socially-salient traits such as IQ-type intelligence are anathema to the Boasian worldview that Fodor and Shenk so desperately wish to protect.
So the heart of this whole conflict really is all about the contrast between the Boasian worldview (per Franz Boas) and the Galtonian worldview (per Francis Galton):
The Boasian worldview emphasizes the power of “Nurture”–Regardless of social class or race, all people are inherently equal and there are no innate differences in mental traits such as intelligence; instead it is cultural and environmental differences which are the root cause of social inequalities. This view is the underlying theoretical framework that supports modern left-wing liberalism.
The Galtonian worldview emphasizes the power of “Nature” –People of different social classes or races show substantial differences in innate mental traits such as IQ-type intelligence. This view is the underlying theoretical framework that supports modern right-wing conservatism (however because it is so highly Politically Incorrect, many conservatives attempt to distance themselves from this currently unfashionable viewpoint).
A large number of studies in the fields of behavior genetics and evolutionary psychology have indicated that human mental traits are highly heritable. Parents who are raising adopted children are unable to transmit their own innate mental traits (such as IQ-type intelligence) to their adopted children (however they can readily transmit mental and physical traits to their own biological children). In contrast biological parents of adopted children (who have never directly participated in raising the children but instead only provided them with their genes) ARE able to transmit mental traits such as IQ-type intelligence. Because these facts (and many other facts from behavior genetics) are essentially able to disprove the Boasian viewpoint, these facts are highly unwelcome and disturbing to social liberals such as Fodor and Shenk who hold strong Boasian views, thus they are keen to exaggerate the importance of any available “scientific sounding” argument that they hope might be construed as raising doubts about evolution and the power of genes.
BOASIAN VIEWPOINT:
Class differences- Children of lower class poorly educated parents are actually just as innately intelligent as children of highly educated professional parents. If only poor parents would learn to use lots of big words when speaking to their children and take care to read lots of books to their children, then the poor children would do just as well in school as the children from upscale home environments.
Ethnoracial differences- Jewish and East Asian children appear to be more intelligent only because they were brought up in cultures which emphasize education. Children of Sub-Saharan African descent appear to be less intelligent only because their ancestors’ Bantu, slave and underclass cultures have been subjugated and discriminated against for over two centuries by evil White Europeans.
GALTONIAN VIEWPOINT:
Class differences- Children of lower class poorly-educated parents tend to be substantially less intelligent compared to children of highly-educated professional parents, and this is largely because of genetic differences. This is because parents whose own intelligence was so low that they failed in school and/or in their career paths are likely to pass on genes to their children that result in lower IQs compared to the IQs of children of higher social class parents who tend to receive genes from parents who were smart enough to have excelled in school and to have flourished in highly competitive professions and career tracks.
Ethnoracial differences- In America, Jewish and East Asian children actually are (on average) substanatially more intelligent than non-Jewish White children and this is probably due to genetic differences. Children of Sub-Saharan African descent actually are (on average) substantially less intelligent than White, Hindu, or East Asian children and this is probably due to genetic differences (perhaps relating to the Natural Selection for higher intelligence imposed by the neccessity for people living in Northern climes to have possessed higher intelligence in order to have survived through the brutal Ice Age winters [Hindus trace their descent from people who invaded from the north into India]).
I suspect that Jerry Fodor and David Shenk greatly dislike the Galtonian perspective on the existence of innate social class and ethnoracial group differences in IQ-type intelligence and other important mental traits, and they fear that Darwin’s theory of natural selection and behavior genetics studies are increasingly offering convincing theoretical and empirical support for the Galtonian perspective.
This fear of the Galtonian view is the true motivation behind the efforts of Fodor to discredit the view that Darwinian natural selection is a valid theory and the efforts of Shenk to deny that DNA-based genetic differences have true agency to cause important differences in mental and physical traits.
endless forms so gone
What a spontaneous, off-the-cuff, not-prepared-in-advance reply that so tidily sums up the human condition. I’m going to cancel my human genetics class next fall.
Even if we assume the worst, that everything the journalist says is true, at best we’d just have to conclude that “inherited variation occurs via genetic mutation, and in rare cases… other stuff”.
Wow, sure topples the entire theory there… >.<
I have published a blog including an email correspondence with Oliver Burkeman regarding this piece if anyone is interested. It is at grimeandreason at blogspot.
I felt it necessary to give it some context and let his side be heard amidst the vitriol. Hope you like.
Mmm, now it seems the reference to my blog on the comments section of Burkemans article has been deleted by the moderators. Good ol’ Guardian.
Having actually read Jablonka and Lamb’s book, which I doubt of Burkeman, in no way do they say that epigenetic inheritance or behavioral or cultural inheritance undermines neoDarwinism or that these types of inheritance are somehow ‘better’ or more common than DNA inheritance. As Dr. Coyne has pointed out the main criticism (which they acknowledge) is ‘where are the examples?’ and ‘what are the mechanisms?.’ However Dr. Coyne’s comment about the rarety of these processes seems a bit off. Outliers can be important biologically, extra large genomes are rare, linear chromosomes in bacteria are rare, polyphagy in insects is rare. I love these science blogs with real scientists, too bad so much time has to be taken up with the likes of Burkeman and not about the real science.
I’ve put up a few thoughts on this at:
http://sciblogs.co.nz/code-for-life/2010/03/22/epigenetics-a-confused-muddle-in-the-media/
When I was a student during my undergraduate biological science degree in 1991-3 the theory (hypothesis) of Lamarkian evolution was thoroughly and vigorously debunked. The classic example cited was that of the blacksmith’s son acquiring the arm strength trait of his father prior to the corresponding environmental influence. It made common sense, for if the only genetic information being transmitted lay in the DNA sequence and this sequence only changed based on random mutation events it would be absurd to consider such a fortuitously coincidental number of mutations to enable increased arm strength within one generation with no selection occurring. However, with the advent of the science of epigenetics, i.e. the inheritance of genetic information that is not related to changes in the letters of DNA, it has become apparent, according to published research, that environmentally modulated characteristics can be passed on from one generation to the next (the methylation pattern is not entirely reset). In humans, this has been mostly studied in disturbances in metabolism that lead to obesity and metabolic syndrome and in psychological disorders. The plethora of genome wide association studies rather than demonstrating a connection between single nucleotide polymorphisms and traits has only served to show that such relationships are tenuous and rarely provide clinically useful information. Aside from highly penentrant mutations in single genes the effect of an alteration in the DNA sequence, which may impact the transcriptional product or binding of transcriptional machinery is likely not to be as phenotypically important as epigenetic modifications that lead to genes being switched on or off, which is the domain of epigenetics. We therefore now know that biological fate is not solely written in the genome but also in the epigenome. The startling realization is that the genome is not just an architectural blueprint being passed in pristine condition from one generation to the next (recombination aside) but also is subject to annotation according to the environmental experiences in the previous generation. From a personal perspective, this remarkable phenomenon certainly does impact the theory of evolution according to what we were taught in the early 90s.
To be fair to the relevance of the epigenetics point (though not the journalist) epigenetic phenomena and the like are relevant to certain philosophical/conceptual discussions within biology in so far as the more noise there is involved in evolution (where noise is anything which isn’t the operation of natural selection) the harder it becomes to read off ‘functions’ from retained phenotypic characteristics, which is relevant if you are a) particularly attached to the concept of function in biology and b) prefer historical (Ruth Millikan-esque) explanations which make liberal use of natural selection as the grounding for the term. I’m not saying Millikan’s position is made impossible by epigenetics, but it makes defending a historical approach to function more complicated.
To read this as saying “Darwin was wrong” however is mental.
Jablonka’s book really hit home for me, but I think its misunderstood by most. The main premise has been contradicticted so much that everyone forgets all the sub-points the author makes so well. I almost wish it would be republished in smaller articles so that the individual components could be debated separately and analyzed accordingly.