Grandma's Experiences Leave An Epigenetic Mark On Your Genes
Dan Hurley writes at DiscoverMagazine:
Geneticists were especially surprised to find that epigenetic change could be passed down from parent to child, one generation after the next. A study from Randy Jirtle of Duke University showed that when female mice are fed a diet rich in methyl groups, the fur pigment of subsequent offspring is permanently altered. Without any change to DNA at all, methyl groups could be added or subtracted, and the changes were inherited much like a mutation in a gene.Now, at the bar in Madrid, Szyf and Meaney considered a hypothesis as improbable as it was profound: If diet and chemicals can cause epigenetic changes, could certain experiences -- child neglect, drug abuse or other severe stresses -- also set off epigenetic changes to the DNA inside the neurons of a person's brain? That question turned out to be the basis of a new field, behavioral epigenetics, now so vibrant it has spawned dozens of studies and suggested profound new treatments to heal the brain.
According to the new insights of behavioral epigenetics, traumatic experiences in our past, or in our recent ancestors' past, leave molecular scars adhering to our DNA. Jews whose great-grandparents were chased from their Russian shtetls; Chinese whose grandparents lived through the ravages of the Cultural Revolution; young immigrants from Africa whose parents survived massacres; adults of every ethnicity who grew up with alcoholic or abusive parents -- all carry with them more than just memories.
Like silt deposited on the cogs of a finely tuned machine after the seawater of a tsunami recedes, our experiences, and those of our forebears, are never gone, even if they have been forgotten. They become a part of us, a molecular residue holding fast to our genetic scaffolding. The DNA remains the same, but psychological and behavioral tendencies are inherited. You might have inherited not just your grandmother's knobby knees, but also her predisposition toward depression caused by the neglect she suffered as a newborn.
Or not. If your grandmother was adopted by nurturing parents, you might be enjoying the boost she received thanks to their love and support. The mechanisms of behavioral epigenetics underlie not only deficits and weaknesses but strengths and resiliencies, too. And for those unlucky enough to descend from miserable or withholding grandparents, emerging drug treatments could reset not just mood, but the epigenetic changes themselves. Like grandmother's vintage dress, you could wear it or have it altered. The genome has long been known as the blueprint of life, but the epigenome is life's Etch A Sketch: Shake it hard enough, and you can wipe clean the family curse.
More on epigenetics.
via @AndreaKuszewski
Whatever happened to my grandparents must have been horrible because they never discussed their religion or cultural background.
Ppen at June 11, 2013 5:21 AM
Eric Blair, please report to room 101 for epigenetic social awareness patterning.
phunctor at June 11, 2013 5:42 AM
I must say that at first blush, this smacks of Lysenkoism. I won't say that it's impossible, but we need to be very careful here because a lot of these theories have been advanced before and have been pretty conclusively disproven.
Cousin Dave at June 11, 2013 6:43 AM
Wasn't there a study about the incidence of diabetes in grandchildren whose grandmothers were pregnant with their mothers during a famine?
nonegiven at June 11, 2013 8:32 AM
Oh dear. Both of my grandmas were in miserable (but long-lasting!) marriages and turned into a couple of real pissers and moaners.
Pirate Jo at June 11, 2013 10:21 AM
"Cousin Dave" pretty much spoke for me, the first reaction I had was "Lysenko is alive, well, and employed."
Not the first time, some claim that while most micro-biologists see evolution at cellular levels most do not believe it can happen in multi-cell organisms - huh?
- - - - -
RANT -
But, "Without any change to DNA at all, methyl groups could be added or subtracted, and the changes were inherited much like a mutation in a gene." Uh, adding and subtracting something in DNA is not changing it?
Or consider breeding. The DNA of the corn on our tables was around centuries ago when American corn ears were almost all about two inches, selection of certain individual plants for planting while discarding others eventually resulted in what now graces our tables. But subsequent generations of corn grown in an area with prevailing east winds will not bend westward if raised in an area of prevailing southerly wind, they will bend to the north. Raised in a greenhouse, I suspect they would not bend in any particular direction
Of course, DNA is not the only player. Not only is "mitochondrial DNA" not exactly the same as "our" DNA, but there is RNA and probably a number of other structures and substructures which are inheritable to one degree or another.
"... psychological and behavioral tendencies are inherited. You might have inherited not just your grandmother's knobby knees, but also her predisposition toward depression caused by the neglect she suffered as a newborn."
Having a grandparent who had a phobia concerning clowns does not mean I will - unless of course she mentioned it every day to me as I was growing up.
And here I had thought we had gotten past "Don't marry him, his cousin went mad so he probably will too." (OK, some types of mental illness may be inheritable - sort of like primarily physical traits like hemophilia.)
John A at June 11, 2013 11:29 AM
Reminds me of Pat Conroy's book "Beach Music" - great read by the way.
Jess at June 12, 2013 7:37 AM
Several big leaps here - which don't seem to be proven yet, based on quick google searches:
1. Direct chemical medication (feeding) is equated with general experiences and behaviors.
Most geneticists will tell you that genes do not influence behavior beyond general personality traits - a point we've hashed out in threads on the "born that way" claim of gay-rights activists.
2. Skipping over the many factors that influence - and inhibit - gene expression.
Since epigenetic factors are weaker influences than actual genes - it's doubtful that much measurable influence is left.
3. Obvious ideological slant - yet more junk science aimed at convincing us that we don't have free will, which is a pet trope of the Left (call it "born that way" for the rest of us...).
Ben David at June 12, 2013 11:55 AM
When you want to make a date with me to give me a BJ, let's talk about choice.
I'm not really on the side of genetics with no pathogen causing a change in the ancestors decision. I can see that what drugs taken before or while a child is in-utero can change the outcome.
Jim P. at June 12, 2013 9:32 PM
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