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Biotech Science

DNA May Carry a Memory of Your Living Conditions From Childhood 252

Posted by Soulskill
from the your-past-is-part-of-you dept.
An anonymous reader writes "Canadian and British scientists have found that how rich your family was when you were a kid — as judged by wealth, housing conditions and occupation of parents — has a huge impact on your current DNA. 'This is the first time we've been able to make the link between the economics of early life and the biochemistry of DNA,' says Moshe Szyf, professor of pharmacology at McGill University. The study did not show whether the DNA changes identified are passed on to offspring, but if so, repeat cycles of poverty could be putting poor children at a serious disadvantage for heart disease, diabetes and lung disorders."
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DNA May Carry a Memory of Your Living Conditions From Childhood

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  • Methylation (Score:5, Informative)

    by Hatta (162192) on Tuesday October 25, 2011 @04:33PM (#37837376) Journal

    The changes in DNA are due to methylation of the DNA, not changes in sequence. This can lead to more or less of a given gene being expressed, but won't lead to any actual changes in the genes.

    • by Synerg1y (2169962)

      Right different living conditions trigger different expressions of the genes. If a chromosome switched on somebody early in life... oh boy lol. Not quite x-men grade there.

    • Yes.... (Score:4, Informative)

      by RobinEggs (1453925) on Tuesday October 25, 2011 @04:46PM (#37837546)
      Yes, but changes in fundamental sequence aren't the only way genes 'change'. Changes in expression constitute almost all of the biological changes that affect to an organism during its lifetime, as opposed to merely affecting its offspring; it's only because of expression changes that you ever go from a fetus to an adult (or from a fetus to a slightly larger fetus, for that matter).

      I mean, presumably you understand this, unless you're able to talk about methylation solely from reading the article, but I don't want anyone to get the impression that 'only' changing the way DNA is expressed is a small feat.

      Expression is *everything*. Almost nothing can be accomplished in any eukaryotic organism without deliberate changes in expression like this; basal transcription (the rate at which your genes are used entirely because the right parts randomly came together with nothing else - like methylation - helping or preventing them) accomplishes almost nothing.

      The human genome is a lot like a computer in that way: almost nothing happens without something specifically telling it to work, and these guys just discovered a whole damn code library.
    • Re:Methylation (Score:5, Informative)

      by ZiggyM (238243) on Tuesday October 25, 2011 @04:55PM (#37837656)
      According to wikipedia on cell reprogramming, these gene expression changes are erased from offspring: "After fertilization the paternal and maternal genomes are once again demethylated and remethylated (except for differentially methylated regions associated with imprinted genes). This reprogramming is likely required for totipotency of the newly formed embryo and erasure of acquired epigenetic changes." See http://en.wikipedia.org/wiki/Reprogramming [wikipedia.org]
      • Re:Methylation (Score:4, Informative)

        by joocemann (1273720) on Tuesday October 25, 2011 @06:21PM (#37838644)

        Nature, Sep 29 2011.

        Scientists show that the protein, Tet3, is responsible of wiping of the male pronucleus methylation patterns after fusion between sperm and egg.

        http://www.nature.com/nature/journal/v477/n7366/full/nature10443.html [nature.com]

        As for the maternal DNA, demethylation, as far as I know, is unknown but occurs as well.

        I'm curious if the disease that arises from these poor conditions is related to epigenetic changes that IMPRINT (are not demethylated, and thus passed through generations). As many are finding out, epigenetics are much more intricate and important than previously conceived.

    • by bahwi (43111)

      While they only looked at methylation, there's also phosphorylation, acetylation, and a few others I'm not familiar with. Each of which can be inherited, and sometimes they are erased. Also changes to histones are 1/2 inherited(usually).

      Also, base changes to the DNA is actually pretty common, which is the reason the sperm cells are heavily protected(not from blunt force however) and generated on a daily basis, and egg cells are even more protected in a female body. You're DNA won't be an exact match but wil

  • by Delgul (515042) <gerard@@@onlinespamfilter...nl> on Tuesday October 25, 2011 @04:33PM (#37837378) Homepage

    "but if so, repeat cycles of poverty could be putting poor children at a serious disadvantage for heart disease, diabetes and lung disorders."

    What is this based on? Perhaps extra robustness is built in for exactly the reason that you may run more risk? So having poor parents may actually give you an advantage...

    • by Derek Pomery (2028) on Tuesday October 25, 2011 @04:39PM (#37837476)

      Yep. From TFA.

      ============
      The study did not show:

              specific disease effects linked to these areas of DNA methylation differences
              or indeed whether there were positive or protective effects
              or whether these changes might be passed on to offspring.

      The study was not designed to look at these areas.
      ============

      I imagine the answer is even that "it depends"

      Presumably extreme poverty to the point of malnutrition would be more harmful than positive.

      • by Synerg1y (2169962)

        What they're more focusing on is that even if conditions in life later improve, they are still saying your at risk for the same diseases. I think...

        Otherwise... no shit malnutrition is harmful? They're saying even when your all nice and rich in your plush down bed, your still in trouble cause you grew up poor. I don't think any of the diseases mentioned are triggerable without external factors present at the TIME of the disease, so this would be a challenge to that train of thought, ex. you get a heart at

        • by Fned (43219)

          There have been studies that the strength of the stress response is largely set in early life. What you stress out over is up to you, but once you stress, the biochemical response is largely based on early trauma.

          So, if you get a heart attack from stress, it's because you were stressed as a child AND your job is killing you.

        • This article is a review, targeted at noobs. If you require something more technical in order to consider it 'worthy' of being read, then pursue the primary literature.

    • They're not saying there's any 'extra robustness' being generated here, and you can't reasonably infer that possibility, either..

      They're saying that the DNA changes, and it makes these people more likely to die of heart disease. If those changes are permanent and affect their germ cells, then their children will also be more likely to die of heart disease.

      If those changes aren't permanent, then their children are only as likely to get heart disease as they were before they lived in a shitty childhood ho
      • Yeah, also from TFA
        ========
        âoeThe adult diseases already known to be associated with early life disadvantage include coronary heart disease, type 2 diabetes and respiratory disorders,â said author, Chris Power
        ========

        But, this study does not link the two. It just notes there are epigenetic changes. It doesn't even, at least as far as TFA seems to say, examine sequences associated w/ any particular disease.

        So, possible, sure, but not the point of the study.

    • by khallow (566160)
      This might explain why people who experience malnutrition early in their lives grow shorter than people who don't. Height is known to have some degree of social advantage (and presumably evolutionary advantage as a result). But dying of starvation because your body grew too fast would be an evolutionary disadvantage.
    • This is based on decades and decades of social experiments throughout history. Scientists have studied the adults who were born during the 1918 influenza epidemic and have seen they have a lifetime of cognitive and health issues. We also see these adverse health effects from the Dutch famine of 1944 [wikipedia.org] and the Romania Abortion Ban [memexplex.com] that led to an unsustainable influx of children to poorly-supplied orphanages, and even more recent studies of children who were in utero when their mothers encountered the stress of [nih.gov]

  • It seems like we've been finding more and more that there are more influences on an organism's genome than just simple heredity and natural selection over a period of several generations. I remember a recent study that suggested that acquired traits might actually be possible to pass on to offspring... if this is the case, we're going to have to revise our models pretty seriously.

    If anything, it will only make evolution a lot more impressive. I don't think we'll be seeing X-men level mutations ever, but
  • ... you are (rewired by) how you live, to twist the cliche. Your offspring might be somewhat rewired by how you lived, too.

    I'm betting the latter is demonstrated eventually, given the clues presented by epigenetics and newfound roles of RNA. I read years ago that the behavior of kittens can be largely predicted by that of the father, even if the father was not present after birth; humans are likely affected by the same mechanisms.

  • I don't know what I should make out of these findings but couldn't it be that kids coming from a "richer" background are fed more nutritiously than maybe a "poor" kid? Couldn't that have an impact on the "appearance" of the genetic material? DNA and life style are such different things that I am not convinced that a correlation between these two are any meaningful at this point.
    • I don't know what I should make out of these findings but couldn't it be that kids coming from a "richer" background are fed more nutritiously than maybe a "poor" kid? Couldn't that have an impact on the "appearance" of the genetic material? DNA and life style are such different things that I am not convinced that a correlation between these two are any meaningful at this point.

      Certainly. TFA is pointing out a plausible (and somewhat unexpected ) mechanism for same. The 'conundrum' the authors were trying to solve was why early environmental conditions should affect health later in life. Their research shows that DNA methylation patterns are stable over time. They conclude that it is POSSIBLE that such changes are deterministic, but other explanations can, and likely do, exist.

  • My parents deprived me when I was a child. I can prove it now since it's all recorded in my DNA!

    (yes, this is a joke. laugh.)

  • Science can definitively say that she's still Jenny from the Block.
  • Great, just another privacy violating way that everything in our life is tracked.

    Who's going to sue God for this clear violation of privacy?

  • epigenetics (Score:4, Interesting)

    by CoderFool (1366191) on Tuesday October 25, 2011 @05:10PM (#37837828)
    Sounds a lot like a Nova program I saw some time ago. It titled 'Ghost in your genes'. It talked about how epigenetics control how your genes are expressed and they had noticed some inherited traits based on whether the ancestors were poor, starving, folk or not.
  • That was from an earlier study 1-2 years back by memory.

    The indication seems strong that environment plays a big part in gene expression and it is absolutely fascinating.

  • I read TFA, and it seems vague what they mean by "rich". I grew up on a farm. We were dirt poor. We got a lot of exercise, as one does on a farm, where whether you eat or not depends on whether you got your chores done. Being on a farm, we ate fairly far down the food chain, commonly fresh foods with almost no processed foods, which we couldn't afford. (This is probably why I never really developed a taste for candy or for overly processed foods.) Sometimes we ate what my dad hunted. (I never did lea

    • by skids (119237)

      So, what health risks did I suffer, as opposed to someone who is rich

      More exposure to environmental irritants and pathogens?

      • by roc97007 (608802)

        I may give you that for pesticides and fertilizers and such, but being on the farm, I lived in the country, and rich tend to live downtown. Doesn't living in a big city have its own collection of environmental irritants and pathogens?

  • "Lingering effect" is not "memory". Calling it memory is bad anthropomorphism, and will contribute to sloppy definitions, fuzzy reasoning, and eventually to pseudo-science. I'm sure the scientist involved understand that the phenomena they're studying is nothing at all like memory, but once this is wrung through the filter of popular press, the distinction gets lost.

    This is how quantum physics gets turned into new-age philosophy, and biomechanics gets turned into healing resonant vibrations.
  • If the DNA was extracted from somatic cells, as the article states (blood), then it cannot show whether there is a heritable effect (passes on to next generation, for you non-biologists). As the article states: "the study did not show whether these changes might be passed on to offspring. Period. You don't need to incorrectly editorialize with the "but if so". There is no need for a non-biologist to make Lamarckian speculation. If the study was on germ line cells in adults that showed methylation, AND
  • In almost all the species the germ line cells, the ones that will become sperm or egg, are sequestered very very early in the development of the fetus. They are also protected more by burying deep in the body, and they undergo fewer cell division compared to other cells. The whole idea is to protect these cells from impact due to life time experience and damage. So it is unlikely the hysteresis on the DNA gets passed on to the progeny.
  • Iceland has the oldest running birth register in the world. From it researchers found that birth weight was affected for a few generations after events such as famine.

    Another experiment involved transferring DNA from one cat into the egg of another, one black and the other white. (Though I can't remember what colour cat they inseminated.) The result was a patchy black/white cat.

    The point I'm making is that we're not purely the product of our main DNA, but also that which triggers DNA to be run (yeah, loo

  • Superintendant Andrews: "We're 25 prisoners in this facility. All double-Y chromos. All thieves, rapists, murderers, child-molesters. All scum." - Alien 3

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