03 December 2013

Inheritance of acquired characteristics

A BBC article has the most interesting news I've read all week:
Behaviour can be affected by events in previous generations which have been passed on through a form of genetic memory, animal studies suggest. Experiments showed that a traumatic event could affect the DNA in sperm and alter the brains and behaviour of subsequent generations.

A Nature Neuroscience study shows mice trained to avoid a smell passed their aversion on to their "grandchildren"... The animals were trained to fear a smell similar to cherry blossom... Both the mice's offspring, and their offspring, were "extremely sensitive" to cherry blossom and would avoid the scent, despite never having experiencing it in their lives...

"The experiences of a parent, even before conceiving, markedly influence both structure and function in the nervous system of subsequent generations," the report concluded...

Prof Marcus Pembrey, from University College London, said the findings were "highly relevant to phobias, anxiety and post-traumatic stress disorders" and provided "compelling evidence" that a form of memory could be passed between generations...
More at the link, and at the original research, published here.


  1. Bear with me here: My maternal grandmother draws well . My mother draws well, as does my father. My mother, father, and I have all worked as artists. My brother draws well. My wife and my youngest son draw well. My older children have a different mother and they don't draw very well despite growing up in an environment full of drawing.
    I find the whole thing interesting as it really makes one wonder about nature versus nurture. How much of us is actually hard-coded in our genes?

    1. I wondered the same thing re musical talent. And the reason I find the subject most interesting is the (perhaps unlikely) possibility that a mechanism like this might explain how Monarch butterflies navigate from Wisconsin to a certain mountain range in Mexico, never having been there before. Nor have their parents. It was their grandparents that left the valley to head north. The navigation itself may be goverened by geomagnetic forces or polarized light, but how does the "knowledge/instinct" to head south exist?

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  3. So, am I getting this right? That it's the traumatic events of fathers (only) that affect offspring? (Because eggs are present from birth and so presumably cannot be changed genetically by anything other than I suppose something catastrophic like radiation.) Is the makeup of the sperm affected permanently by some fear-inducing experiences of the father, I wonder, or is it affected only by recent events and so can vary for offspring produced in different years?

    1. I see what you mean and until very recently you would have been exactly in line with modern science. But the evidence from this research argues against that hypothesis. Here is a good summary since no one can afford to subscribe to Nature Neuroscience:

      "Dias found that both mothers and fathers can pass on a learned sensitivity to an odour, although mothers can't do it with fostered pups, showing that the sensitivity is not transmitted by social interaction. [...] The inheritance takes place even if the mice are conceived by in vitro fertilization, and the sensitivity even appears in the second generation (grandchildren). This indicates that somehow, information about the experience connected with the odour is being transmitted via the sperm or eggs."

      One of the amazing things happening in biology right now is that the nature vs. nurture debate is being unified by a new field called epigenetics. The core of the field is the discovery that experiences we have can turn genes we already have on or off, or cause them to produce more or less of a protein.

      This isn't magic mind reading by cells. Rather it is likely caused by things like stress hormones, extended low blood sugar indicating starvation, etc.

      The implication of this study is that it may be possible for these epigenetic markers to be passed down via the gametes. Since these markers that silence/activate genes may be attached to the DNA in eggs as well as spermatozoa it is possible that the effect can be passed down matrilineally as well.

  4. Epigenetics actually isn´t thar recent knowledge, it has been around for a while. (See http://www.ncbi.nlm.nih.gov/pubmed/17998809) There are a lot of interesting studies in the field, and the basic mechanisms are actually quite well known (the details of course are highly complicated and there´s much work to be done - even small things like what food we eat could have great impact on our epigenetic makeup).

    I personally found the Överkalix study to be immensly interesting - the idea that our bad health now might have positive effects as far as two generations down is fascinating, and I think it poses interesting questions for our general understanding of cause and effect in medicine. (For the Överkalix study see here http://en.wikipedia.org/wiki/%C3%96verkalix_study)


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