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Epigenetics: Early abuse changes gene expression in children


From ScienceDaily:

Children who have been abused or neglected early in life are at risk for developing both emotional and physical health problems. In a new study, scientists have found that maltreatment affects the way genes are activated, which has implications for children’s long-term development. Previous studies focused on how a particular child’s individual characteristics and genetics interacted with that child’s experiences in an effort to understand how health problems emerge. In the new study, researchers were able to measure the degree to which genes were turned “on” or “off” through a biochemical process called methylation. This new technique reveals the ways that nurture changes nature — that is, how our social experiences can change the underlying biology of our genes.

The researchers found an association between the kind of parenting children had and a particular gene (called the glucocorticoid receptor gene) that’s responsible for crucial aspects of social functioning and health. Not all genes are active at all times. DNA methylation is one of several biochemical mechanisms that cells use to control whether genes are turned on or off. The researchers examined DNA methylation in the blood of 56 children ages 11 to 14. Half of the children had been physically abused.

They found that compared to the children who hadn’t been maltreated, the maltreated children had increased methylation on several sites of the glucocorticoid receptor gene, also known as NR3C1, echoing the findings of earlier studies of rodents. In this study, the effect occurred on the section of the gene that’s critical for nerve growth factor, which is an important part of healthy brain development.

There were no differences in the genes that the children were born with, the study found; instead, the differences were seen in the extent to which the genes had been turned on or off. “This link between early life stress and changes in genes may uncover how early childhood experiences get under the skin and confer lifelong risk,” notes Seth D. Pollak, professor of psychology and pediatrics at the University of Wisconsin, Madison, who directed the study. More.

Or, as one expert put it, “If you think love conquers all, you’re not paying attention.”

If this finding holds up, it may provide two valuable tools:

It may shed some light on why children who were mistreated early in life can be difficult to rehabilitate. Many (not all, of course) continue to behave as if they were living in a high threat, low attachment environment—when they have in fact been living for years in a low threat, high attachment environment. That is, some children don’t seem to adjust to their actual circumstances over time, as one might expect. Something is wrong, but what? “Born bad” just doesn’t cut it by way of an explanation any more. We want more specifics.

Second, a clearer idea of what is going on would enable us to develop better strategies for rehabilitation. Which is the main reason for studying the problem anyway.

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I believe that epigenetics is an issue for Darwinian evolution because some of the examples that are used to justify Darwinian evolution are not genetic but epigenetic and not really evolution. For example, Darwin's finches which represented a prime example of evolution in action and helped persuade many people of the power of natural selection was not Darwinian evolution. So the Darwinist is now under obligation to show that any changes are not epigenetic. It is a recent phenomena for the evolutionary biology community in the sense that few books discussed it. Eva Jablonka's book was the first time I heard of it and that was when Allen MacNeil introduced it here about six years ago. jerry
Environment affects the way some genes are expressed. This has been known for decades
Sure, but what would a naturalistic explanation look like? For starters: which environmental chemicals represent abuse and or neglect? Box
DavidD, Presumably, even the capability for epigenetics evolved, providing organisms the ability to evolve in several modes depending on the environment. This means that in one modality, related organisms could be separate species and in another modality they could be the same species. The miraculous nature of evolution is even more magical with the phenomenum known as "alternation of generations." This is where only every other generation is the same. One generation might be a polyp, the next a medusa form. Check out sea jellies and sea lettuce. And that's another reason that I quit believing in the failed 19th--century speculation called evolution. -Q Querius
Querius "Now that epigenetics has been discovered, we can work this in as well, calling it a “mechanism” that itself evolved through epigenetics." Except that epigenetics while creating amazing variety is a dead end for evolution because it only oscillates organisms back to full circle. It doesn't allow a kind or type of organism to blindly for no reason mutate beyond it's species barrier. If it does mistakenly allow a freak show to emerge, that's what death & kill switches are for. That's what species boundaries do. Just ask any Biotech company that breaks barriers and boundaries rather than using those yet to be identified amazing evolutionary mutating mechanisms which morph more and more complexity with leaps and bounds (or out of bounds). The very reason Biotechs even exist is because of those stupid "Bad Designer Arguments". In other words, if nature had got it right in the beginning, the collective genius of imperfect humans would not have had to tinker to fix it correctly. As you can see, the gmo industry has done wonders for the planet's health. What would the natural world have done without them? What more evidence does one need that evolution is true given the health of our planet and climate change ? DavidD
A.B. "But, again, the current work is merely providing the mechanism behind what we knew for decades." Mechanisms? Mechanisms? How do blind unguided forces evolve & manipulate chemical soups influenced by physics to create nano-machine mechanisms controlled by sophisticated complex information ? Oh sorry, that's Abiogenesis and nothing to do with evolution which is anything your side says it is. No wonder the natural world is falling apart. DavidD
Yes, exactly. If we assume that all genetic variation was the result of evolution, we can conclude that observed variation is due to evolution, all of which has been intuitively known for centuries. Now that epigenetics has been discovered, we can work this in as well, calling it a "mechanism" that itself evolved through epigenetics. Additional discoveries, while almost always completely unpredicted, pose no problem to the theory. For example, the presence of junk DNA is strong evidence for evolution, but the discovery of function in junk DNA, which is being prophylactically renamed "non-coding DNA" or "genetic climate change" is also strong evidence for evolution. ;-) -Q Querius
It is still about how a gene is (or is not) expressed. This means that the genetic variation must arise from somewhere (mutations) and can be acted on by natural selection. Epigenetics has simply given us a different way to think about variation. But, again, the current work is merely providing the mechanism behind what we knew for decades. Acartia_bogart
Mapou "OW, a species can change and adapt to its environment without the involvement of Darwinian evolution, i.e., no random mutations are needed. So no, Darwin’s finch beaks (and similar variations in a species) are not examples of Darwinian evolution." And that is the main point and that is what is hated by the kool-aid crowd who are obsessed with every single little change as being Darwinian. This is NOT about DNA mutating or morphing into anything different, this is specific switches being either turned on or off which creates a response into how the same exact DNA is expressed. As Cornelius Hunter has always state, no one is arguing there is no change, but is that change anything to do with evolution and the answer is simply no. DavidD
The whole point of epigenetics is that it changes the genetic makeup of not just an individual but a group of individuals that are subjected to the same environmental pressure. Furthermore, the changes can be inherited, that is, passed on to offsprings. It happens within a single generation. IOW, a species can change and adapt to its environment without the involvement of Darwinian evolution, i.e., no random mutations are needed. So no, Darwin's finch beaks (and similar variations in a species) are not examples of Darwinian evolution. Mapou
#1 "Environment affects the way some genes are expressed." The interesting phase in the morphing of neo-Darwinist verbiage will come when it is cornered enough to clearly acknowledge that the expression of genes affects the DNA transformations (mutations). Presently only few heretics, like James Shapiro, dare suggest it. That will be last nail for the "central dogma" and "mutations are random with respect to fitness" slogan. Not that any of that can falsify neo-Darwinism or affect its pretense of omniscience. nightlight
DavidD, You have a very strange view of evolutionary biology. The control of gene expression has been a central topic in molecular biology since the 1970s, I don't know of anyone who has ever claimed "cells do nothing but spitting out copying errors". As far as gene environment interactions, the math to deal with these was built by RA Fisher, one of the founders of modern "Darwinism", so it's a bit rich to say evolutionary biology hasn't included it. wd400
The other interesting thing about this epigenetics and predispositions for inherited behavior, everyone has free will not to act out on some predisposition to smoke, be an alcoholic, be a woman or child abuser, or even act out on a predisposition for homosexual behavior. Of course the "Rape is an Evolutionary Adaptation for spreading one's DNA" folks won't like this, but tough cookies DavidD
Acartia Bogart: "Environment affects the way some genes are expressed. This has been known for decades" So ? For decades you Priests have been shoving down everyone's throat that cells do nothing but spitting out copying errors, but suddenly we get righteous indignation that they've known about this all along. It's amazing how easy it is for the theory to evolve of you've got the right ideologues pimping for Chuck DavidD
Environment affects the way some genes are expressed. This has been known for decades Acartia_bogart

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