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We are not nearly as determined by our genes as once thought

• loraa 8y ago
  I know exactly where this one is headed..
• loraa 8y ago
  "maybe I am an apache attack helicopter in a mans body.."
• falcor84 8y ago
  As someone who actually does have a bit of knowledge of genetics and molecular biology, I couldn't get through all the fluff. What are the actual news presented here?
  • Scaevolus 8y ago
    It seems to be "genetics are very complicated, and because many traits aren't Mendelian and polygenic additive models are oversimplified, they are useless." Mostly, it seems to copy common misconceptions about statistics. The people working with polygenic models understand that the models don't perfectly represent reality, but that doesn't make them useless! They give estimates for various traits (like height) that have been tested to correctly explain some fraction of the variance in a population. Models aren't reality, hence the name!
  • api 8y ago
    TL;DR: we don't understand genetics well enough to make definite statements about the degree to which genes determine phenotypes, how this happens, how malleable or environmentally influence-able it is, etc. As a result we should not dogmatize statistical inferences from genomics and heritability studies, especially if such dogmas influence policy or prejudice. I studied genetics quite extensively and none of that is news to me at all. Dogmatic genetic determinism is Dunning-Krueger effect territory, not because it's impossible but because we don't know enough to be certain enough about it to make it useful. Trying to assert otherwise is wishful thinking, usually by people who really wish there were a way to make scientifically credible assertions about the value of human beings based on their genetic lineage (hint hint). The best way I can describe what seems to be happening with genes and development is that it's something loosely analogous to procedural world generation in games. You have this genetically encoded series of very complex chemical structures that when embodied in a given environment and "executed" via energetic processes generate a phenotype. The phenotype is the product of a set of genes embodied in an environment. Beyond protein structure genes do not contain any kind of "blueprint" for anything any more than e.g. a fractal equation actually contains its complete output. The blueprint analogy is even wishy washy in terms of direct protein structures due to things like RNA transformations, epigenetics, proteins influencing how other proteins form, etc.
    • Kim_Bruning 8y ago
      I really like the idea of comparing procedural generation to genetics! I'll use that myself next time I need to explain things.
• buboard 8y ago
  biorxiv is not a journal
  • Bartweiss 8y ago
    This is actually a good point. I love arXiv and what it's done for article access, and I hope biorXiv takes off. But "in the online journal Biorxiv" is still a sort of ridiculous attempt to drum up credibility. Heck, I'd be more inclined to overlook it, but the mis-capitalized title and nonstandard italics both serve to make it look more like a traditional journal than it really is. (And, of course, it's being cited to prop up a really sloppy article.)
• ineedasername 8y ago
  I thought this was already a fairly established fact vis a vis epigenetics and the mechanisms behind which genes actually get expressed.
• biomcgary 8y ago
  The author's fear is that current views of genetics will lead to horrible policy decisions; thus, genetic determinism should be undermined. Evidence against simple, linearly addititive genetic determinism is used to argue against genetic determinism more broadly. I am very much in favor of genetic agnosticism, the position that we are currently very poor at predicting complex traits from genetic data (and may always be). Failure to predict does not negate genetic determinism per se. However, clonal animals and human twins provide fairly strong evidence of the limits of genetic determinism.
  • ummonk 8y ago
    Identical twins raised separately end up rather similar in adulthood. So human twins actually provides fairly strong evidence that genes substantially (though not exclusively) determine how we end up.
    • solveit 8y ago
      They end up remarkably similar, but it turns that remarkably similar isn't nearly similar enough to be useful in most contexts. In fact, I think the biggest lesson of the social sciences is a deeper intuitive understanding of how individual variation will completely dominate any other statistical factor in anything made of people, and how fortunate we were that the physical sciences were much simpler.
      • 1_over_n 8y ago
        Exactly. "Remarkably similar" != "Identical" (using the truest version of the word identical - exactly the same)
      • philipov 8y ago
        Stanford's Youtube channel has a series of lectures for Robert Sapolsky's class on Human Behavioral Biology, and he spends a good amount of time on genetics there. The view he presents there is that there is no such thing as a gene FOR something, because the effect of a gene is a function of the environment in which it is expressed. For example, it's incorrect to think in terms of a gene for depression, but it is more reasonable to think of a gene that will make you vulnerable to depression if you are exposed to strong stressors during childhood. I recommend watching the entire playlist, but I've linked to the punchline at the end of Behavioral Genetics II. I've linked to him discussing the heritability of plant IQ, followed by the heritability of depression example I alluded to earlier. https://youtu.be/RG5fN6KrDJE?t=3200 https://youtu.be/RG5fN6KrDJE?t=3200 Again, I recommend watching the entire lecture if you have an hour and a half, both lectures if you have 3 hours, or all the lectures if you have, like, 40 hours.
• mattnewport 8y ago
  No mention of twin studies? The article doesn't appear to distinguish between genes as unit of inheritance and heritability of traits which many studies seem to indicate is quite significant.
  • petermcneeley 8y ago
    I think its common to focus on the similarity of identical twins. But I actually think the variance in identical twins is far more interesting because it suggests something very radical about the role of development in the non biological sphere. I can give you one example that gave me pause and you should know. At the EAC cafe there were twin kitchen staff. However one was lean and the other was more tubby. Unless there was a transcription issue in the gene for metabolism I think there were identical genes at play. Thus the resulting variance is non biological developmental. There are tons of other anecdotal observations I have made in my experience with identical twins. I think any variance (assuming perfect cloning) suggests something that is non biologically determined.
    • SamReidHughes 8y ago
      That variance is partly biological: randomness in early development, genetic differences between identical twins, exposure to pathogens and immune response at an early age, and with women, X chromosome mosaicism. A big sign of this is that if one identical twin is gay, the other is still usually not gay.
    • mattnewport 8y ago
      Hey Peter! Twin studies are one of the more powerful tools we have to try and separate out the effects of genetics, shared environment and non shared environment in humans. Shared environment represents what twins raised in the same household have in common in their environment and non shared environment what is still different. Studies of heritability tend to indicate for many traits that genetics have the largest role and (perhaps surprisingly) non shared environment the next largest with shared environment having the smallest (though often still important) role to play. Your example of the twins would be a classic case of non shared environmental influence. Certainly nobody claims that environmental influences are not important and like most things the details are complicated and leave much room for debate over the exact role of each component in determining traits. In some ways it is true that the environmental factors are the most interesting since they are the ones we have most control or at least influence over for ourselves and our children.
• Real_S 8y ago
  I agree with most of the comments made so far, that this article is terribly written and generally uninformative. Nevertheless, I believe that the author in primarily trying to convey that "genes" themselves are far less important that science used to think they were. Although this isn't huge news to geneticists, it may be to some. However, if this is the intended message of this article, much of his writing is, at best, slightly off topic. Even though the protein coding regions of the genome are far less important than we first believed, that does not mean that genetic heritability is necessarily unimportant. I would have loved to see a discussion about the heritability caused by non-protein regions of the genome. Maybe another time...
  • feanaro 8y ago
    > Even though the protein coding regions of the genome are far less important than we first believed, that does not mean that genetic heritability is necessarily unimportant. In fact, it cannot be unimportant since evidence showing genetic heritability (in the sense of explaining a part of phenotype variance between ancestor and descendant) is not invalidated by the fact that it does not explain the variance completely.
• 8bitsrule 8y ago
  "Governments followed a famous 1938 United Kingdom education commission in decreeing that, “The facts of genetic inequality are something that we cannot escape,” and that, “different children ... require types of education varying in certain important respects.” It's unfortunate that some people will leap into new and unsettled scientific 'discoveries' as if they were gospel. It's as though cultural responses to the old 'supreme authority' were simply transferred onto a new one. Sadly, in this case, the historical outcome is a prime example of that danger. The tentative - and upgradable - nature of science must be communicated in the teaching of it, including the news and the reference works. Now and then it's only human to admit 'I don't know'. (As Jacob Bronowski took pains to demonstrate in 'The Ascent of Man'.)
• georgewfraser 8y ago
  The title of this article should be, “We are exactly as determined by our genes as once thought, but we don’t know precisely how this works”. We can estimate how genetically determined a trait is by comparing identical to non-identical twins, or by comparing full siblings to half siblings and adopted siblings. There is a long history of data in this area which is just as valid today as ever. This article points out that we know very little about how specific genes determine specific traits. True. But we can know that a trait is genetically determined without knowing how a trait is genetically determined.
  • YUMad 8y ago
    While identical twins share same genes, they also share the environment in uterus. I wonder what would be the result of gestating identical twins in different wombs.
    • infradig 8y ago
      Or just compare identical to non-identical twins?
  • chongli 8y ago
    We don't even have to do that. Just compare humans to mice or fruit flies or nematodes. Genes make all the difference there. If people can accept that genetics cause the huge variations between species, why not accept the small variations between individuals? Why this "100% nurture" fundamentalism?
    • opwieurposiu 8y ago
      The left abhors facts of genetics just as the right abhors facts of climate change. In both cases there is a lot of virtue signaling going on, they know that the science is not on their side but they can not admit it because to do so would get them cast out of their in-group.
      • tormeh 8y ago
• 1_over_n 8y ago
  I did in vivo brain surgery using animal models. The rats were all from specific strains geared towards being almost genetically identical as possible. I can say, each one of these rats developed in a completely unique way from behaviour through to anatomy despite being kept in a highly controlled environment (same food, light, water, routine, conditions etc). Even the location of their brain anatomy differed highly. So even in almost genetically identical models, there is a high degree of individual variability.