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Medicine Science

Childhood Stress Leaves Genetic Scars 334

Posted by Soulskill
from the stories-told-in-base-pairs dept.
sciencehabit writes "Traumatic experiences in early life can leave emotional scars. But a new study suggests that violence in childhood may leave a genetic mark as well. Researchers have found that children who are physically abused and bullied tend to have shorter telomeres — structures at the tips of chromosomes whose shrinkage has been linked to aging and disease."
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Childhood Stress Leaves Genetic Scars

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  • by LifesABeach (234436) on Tuesday April 24, 2012 @05:45PM (#39788723)
    Could the telomeres of chromosomes be lengthened? Would this theropy have the affect of causing the cell to handle longevity better?
    • Yes, cells with lengthened telomeres are made by many people - they're called cancer cells.
    • Longer telomeres would increase the risk of getting cancer at an earlier age.

    • by jd (1658) <imipak@nOSPam.yahoo.com> on Tuesday April 24, 2012 @06:43PM (#39789357) Homepage Journal

      The ideal therapy would involve determining the probability of a dangerous mutation then resizing all the telomeres accordingly. You don't want excessively long telomeres (it's an intentional self-destruct mechanism for preventing a cell damaged over time from becoming malignant) just as you don't want telomeres being too short.

      Cancer cells are not necessarily ones with over-long telomeres - typically what happens is that the cell's mechanism for shortening the telomeres breaks so that the cell can replicate forever. That doesn't, however, mean that it will or that the replication will occur in a timeframe that's of any significance. You'd have to have additional damage to cell mechanisms for that. If you can modify telomere length on-the-fly, the easiest one is to shorten all the telomeres in a person to something that'll only allow a few copies, then close to the deadline lengthen them just a little. That way, if a cell goes nuts and replicates excessively prior to the telomere system breaking, it'll suicide before it reaches the point of being able to replicate forever.

      A better option, though considerably further into the future, would be to modify the repair mechanism in DNA to be rather more reliable. The better-able DNA is at fixing damage, the longer you can make the telomeres without it causing harm. As it stands, the mechanism has limited value. So much so that mtDNA has no such mechanism at all and can handle such a state just fine.

      Of course, it helps that mitochondrial DNA is much shorter. The current nucleic DNA is a combination of the original nucleic DNA plus a lot of DNA from symbiotic organisms that became part of the cell and eventually became part of the nucleus, PLUS a great many retroviruses. Perhaps 8-10% of nucleic DNA is from fossil viruses (some still active) and according to recent studies perhaps another 40% is from other external sources.

      It aught to be possible to take a fully-sequenced (and I MEAN fully-sequenced) human genome and optimize it. There'll be plenty of genes that belong to fossil lifeforms that serve no useful purpose as far as the human host and the microflora within the host are concerned. (That's over 5,500 lifeforms, so you've got to be very sure of these things.) Decrufting and compacting the human genome would likely reduce the risk of dangerous mutations. It may be that replacing the central DNA core with an XNA core would also help, but I saw nothing in that article about whether XNA molecules have the capacity to unwind properly and replicate, only that XNA had been constructed and was able to carry the same base pairs. This solution is in the FAR future (Star Trek timeframe at best) but there's nothing there that breaks any known rule. We can already do some of the steps, the main reason I'm putting it 500+ years in the future is that the problem space grows exponentially with the number of genes and even quantum computers aren't going to have sufficient power to handle a space that large for a very very long time. If ever. GM is unpredictable enough when adding/deleting single genes, but compacting DNA would involve wholesale rewrites of the genetic code.

  • On a related note... (Score:5, Informative)

    by HomoErectusDied4U (1042552) on Tuesday April 24, 2012 @05:54PM (#39788829)
    A study (http://www.pnas.org/content/109/17/6490.full) was published in PNAS today showing how low-ranking monkeys have worse immune systems than high-ranking monkeys. (In monkey societies, 'high-ranking' is a euphemism for bully.) We've known for a long time that subordinate monkeys have worse health and live shorter lives in general than dominant monkeys, but this is one of the first studies that describe how this actually happens, genetically and physiologically.
    • We've known for a long time that subordinate monkeys have worse health and live shorter lives in general than dominant monkeys, but this is one of the first studies that describe how this actually happens, genetically and physiologically.

      In human societies, we've known about this since the Industrial Revolution. -_- It's hardly a shocking finding that when you get the crap kicked out of you and live in constant fear, under stress, and working hard, you die sooner.

    • by DigiShaman (671371) on Tuesday April 24, 2012 @06:49PM (#39789403) Homepage

      I've heard of this. But what I want to know is this. Are the shortening of the telomeres caused by...

      A:) poor diet, exercise, and lack of nutrition.
      or
      B:) Stress hormones causing destruction of our own DNA.

      If it's "B", I'm really fucked! I have so much stress these last 5 years that I've about had breakdown (life, economy, working long hours to keep my job..ect). I don't drink, smoke, or do anything physically abusive. But I feel like I've aged 10 years. Now multiply that by however many American's and Europeans are going through the same shit in the Great Depression part 2.

      • by Cow Jones (615566) on Wednesday April 25, 2012 @07:09AM (#39793169)

        I have so much stress these last 5 years that I've about had breakdown (life, economy, working long hours to keep my job..ect). I don't drink, smoke, or do anything physically abusive. But I feel like I've aged 10 years.

        Have you ever thought about indulging yourself a little and having a beer once in a while, just to take the edge off a little? Too much of anything is bad, of course, by definition, but a little can go a long way. I've long had the suspicion that people in cultures where alcohol is completely prohibited tend to get too worked up over small and unimportant things. I also treasure the evenings where my friends and I drink a little more than we should; we get to collectively step out of our normal controlled selves for a while, bond, and do stupid, childish stuff. In an utterly unscientific way, I suspect that whatever harm the alcohol does to our bodies will be offset by the fun we have. And even if our bodies are harmed a little, and our lives shortened a little, at least we had fun.

        Just my 2 cents.

    • by jd (1658) <imipak@nOSPam.yahoo.com> on Tuesday April 24, 2012 @06:53PM (#39789437) Homepage Journal

      It's likely related. Telomeres don't shorten on their own. One (of several) environmentally-controlled systems in the cells is the epigenome - a string of proteins that controls how DNA is interpreted. It may well be that emotional stress alters the epigenome in areas affecting the immune system and telomeres.

      (There's some evidence that highly stressed adult humans are also more susceptible to cancer, and cancer again is linked to both the immune system and the telomere system.)

      I think we're going to find that a number of things we've taken for granted as the "right way" for a society to function will prove to be carcinogenic and/or physically toxic. It will be interesting to see if that results in societies changing or whether they deem subjecting carcinogens and toxins on others to be a fundamental freedom (or that people are expendable anyway, or that the science isn't agreed on by 107.3% of all toothpick manufacturers, etc).

      • by tragedy (27079) on Tuesday April 24, 2012 @10:16PM (#39791013)

        Telomeres don't shorten on their own, as you say. The traditional understanding is that they shorten when DNA replicates itself. Cell splits into two copies and the copies have shorter telomeres, limiting the number of times they can reproduce. Applying Ockham's Razor, it seems that the simplest explanation for two otherwise similar individuals of similar ages to have differing telomere lengths is that the individual with the shorter telomeres has experienced more cell death over their lifetime, so more of their cells are replacements. That can be explained by exposure to drugs or alcohol in the womb, poor nutrition, heightened stress levels causing cell death through various mechanisms, as well as plain old physical trauma. Given that explanation of how growing up in an abusive home could lead to shorter telomeres, is another explanation necessary? Does there have to be some special mechanism shortening telomeres to explain the results of this study, or does the traditional explanation that telomeres shorten with every cell division cover it?

    • Of course, monkey social hierarchy is often enforced by the high ranking males mounting the lower ranking males. Not sure "bully" is an appropriate comparison for schoolyards. Jails maybe.
      • ...the high ranking males mounting the lower ranking males.

        And people say gay sex isn't natural why again?

        • interkin3tic's post seems like an example of sex-related behavior that's about something besides the sex.

        • by tftp (111690)

          And people say gay sex isn't natural why again?

          The same high ranking male can utilize beating with a stick, hitting with a stone, biting, throwing off the tree, chasing away from food... all these things are natural, but it doesn't mean that they are socially progressive or good for you. They are all punishments.

  • Not surprised (Score:5, Insightful)

    by Anonymous Coward on Tuesday April 24, 2012 @06:05PM (#39788971)

    It's already known that stress can seem to accelerate aging. Ever see those pictures of presidents before a term, then after? 4 years passed for everybody else, but it looks like they aged 10 years.

    Psyche and soma are not fully distinguishable.

  • This just smells like bad science. Not that it's impossible, but a claim like this is pretty extreme and I'd like to see it replicated several times before believing it.
    • by geekoid (135745)

      Actually, it was pretty good science.
      More study recommended? of course. I can't find anything in their methodological the would be bad. What did you find?

      What's that, you haven't read the study? ah, STFU.

      • You forked over the $32 to read the study? Yeah, sure you did. The abstract said nothing about it being a double blind study or much else about methodology yet it asserts that as little as one "violence exposure" reduces telomere length the equivalent of living ten years? It doesn't even define "violence exposure" nor give any proposed mechanism why this would be the case (and why something like breaking your leg playing tennis wouldn't). Maybe the study answers these questions, but I doubt it and it isn'
  • FTFA: ...But the connection between telomere length and health and longevity is far from clear. "There's a lot of doubt in the field," notes Joao Passos, a cellular aging specialist at Newcastle University in the United Kingdom who was not involved in the research. "For as many studies that show telomere length as a good predictor of health outcomes, there are as many that find no relationship."...

    Also, with a bit of work I bet they could find something else the test subjects had in common and thus be cl
  • Remember when they used to teach that humans exhale co2, inhale oxygen? And plants "inhale" CO2, and release oxygen? Turns out they take in oxygen [google.com], too.

    It used to be taught that environmental factors during an organism's lifetime (malnutrition, etc.) did not have an effect on the genetic heritage of offspring (you get a "clean slate" of DNA, so to speak). The opposing idea, that, e.g., giraffes are tall because their ancestors had to reach up to the tall leaves, and then they had long-necked kid giraffes wa

    • But here we are with a study that says environmental factors can leave a genetic mark.

      Is this the first time you've heard of epigenetics?

    • by TheEmperorOfSlashdot (1830272) on Tuesday April 24, 2012 @08:06PM (#39790119)

      It used to be taught that environmental factors during an organism's lifetime (malnutrition, etc.) did not have an effect on the genetic heritage of offspring (you get a "clean slate" of DNA, so to speak). [...] But here we are with a study that says environmental factors can leave a genetic mark.

      The study was about somatic cells, eg "body cells" that make up the specialized tissues of your body. Your offspring are formed from germ cells, found in your gonads, and consequently your offspring can only inherit DNA from your germ cells, but never your somatic cells (except in the case of cloning or other artificial techniques).

      Telomeres are the "endcaps" of chromosomal DNA. Every time a chromosome is copied, a small portion at the ends of the chromosome get "left off" of the copy, which limits the number of time a cell can divide before the telomeres are consumed and functional DNA segments begin to be deleted. This (usually) prevents cells from reproducing in an uncontrolled fashion, and it's one of your body's main defenses against cancer. That's how it works in somatic cells.

      Germ cells, on the other hand, can express a ribozyme called "telomerase," which can bind to the ends of a chromosome and extend the telomeres. This is why animals can reproduce indefinitely even though 99% of their cells are "mortal." (As others have pointed out, when a somatic cell begins to express telomerase it's usually cancer.)

      The upshot of all of this is that shortened telomeres in your somatic cells will have no direct effect on your offspring. This particular study in no way supports the idea that environmental factors are responsible for genetic changes in offspring. Your post is therefore ill-informed even if your thesis is correct ("almost everything they teach in American public school is either wrong or simplified to the point of uselessness?").

      To rectify your error, your homework assignment for tonight is to study the enzymes called "telomerase" and "reverse transcriptase," followed by learning the "central dogma of biology."

      Dismissed.

  • what doesn't kill 'em makes 'em weaker.

  • I think they have the cause and effect backwards. It is not that abuse causes short telomeres, rather, the short telomeres cause abuse. No, really. Most child abuse is from family members ... who also have the short telomeres in most of these cases. Short telomeres also make people bad and turn them into abusers, bank robbers, and even spammers. And I think Anonymous Coward has short telomeres, too.

"Everything should be made as simple as possible, but not simpler." -- Albert Einstein

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