Sunday, September 09, 2012

Not a lot of separation. And yet separate, when it comes to genetics

A bit in the Sunday times on fatherhood and epigenetics:

Before I began reading up on fathers and their influence on future generations, I had a high-school-biology-level understanding of how a man passes his traits on to his child. His sperm and the mother’s egg smash into each other, his sperm tosses in one set of chromosomes, the egg tosses in another, and a child’s genetic future is set for life. Physical features: check. Character: check. Cognitive style: check. But the pathways of inheritance, I’ve learned, are subtler and more varied than that. Genes matter, and culture matters, and how fathers behave matters, too.  
Lately scientists have become obsessed with a means of inheritance that isn’t genetic but isn’t nongenetic either. It’s epigenetic. “Epi,” in Greek, means “above” or “beyond.” Think of epigenetics as the way our bodies modify their genetic makeup. Epigenetics describes how genes are turned on or off, in part through compounds that hitch on top of DNA — or else jump off it — determining whether it makes the proteins that tell our bodies what to do.  
In the past decade or so, the study of epigenetics has become so popular it’s practically a fad. Psychologists and sociologists particularly like it because gene expression or suppression is to some degree dictated by the environment and plays at least as large a role as genes do in the development of a person’s temperament, body shape and predisposition to disease. I’ve become obsessed with epigenetics because it strikes me as both game-changing and terrifying. Our genes can be switched on or off by three environmental factors, among other things: what we ingest (food, drink, air, toxins); what we experience (stress, trauma); and how long we live.  
Epigenetics means that our physical and mental tendencies were not set in stone during the Pleistocene age, as evolutionary psychology sometimes seems to claim. Rather, they’re shaped by the life we lead and the world we live in right now. Epigenetics proves that we are the products of history, public as well as private, in parts of us that are so intimately ours that few people ever imagined that history could reach them. (One person who did imagine it is the French 18th-century naturalist Jean-Baptiste Lamarck, who believed that acquired traits could be inherited. Twentieth-century Darwinian genetics dismissed Lamarckism as laughable, but because of epigenetics, Lamarckism is staging a comeback.)

There are certain problems with the above text though in general I agree with its sentiment. First the problems: No, Lamarckism is not staging a comeback - Larmarckism held that in general acquired traits are inherited.

The degree to which we can make choices is also shaped by prior inputs and states,  and we don't know to what extent what was shaped by what because it's all interconnected.

But yeah, stop messing with the future in a bad way.

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