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If you smoke, your grandchildren could pay for it

Posted by Kevin Hartnett  March 19, 2013 09:00 AM

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Over the last decade, our knowledge of the human genome has exploded, but it often seems like the more we learn, the deeper the mystery grows. We have a basic understanding of what many of our 23,000 genes do, but that understanding has not translated into a particularly great ability to predict who among us will develop common pathologies like diabetes or coronary artery disease.

But the cutting-edge field of epigenetics is trying to change that. Geneticists working in this area are looking for heritability mechanisms that go beyond our genes, and researchers at UCLA recently made an important discovery in that direction.

John Torday and Virender Rehan wanted to know if smoking can have negative health impacts multiple generations into the future. To test this, they injected female rats with nicotine and then analyzed the lung function of their progeny. What they found was stunning: Two generations down the line, the grandchildren of the nicotine-injected rats were more likely to have asthmatic lungs than control subjects. And, this occurred in the absence of any genetic mutation across the generations.

So, how is it that a disease like asthma could become heritable without a genetic change? To answer that, the researchers (and their geneticist peers) are increasingly looking to the 98 percent of the human genome that is not directly involved with protein coding (as opposed to the 2 percent of the genome that is made up of those 23,000 genes). This vast territory used to be referred to as "junk DNA" for its apparent purposelessness, but it's increasingly clear the pejorative was misapplied: This junk DNA seems to be critically involved with gene expression, and it's here that epigenetic influences like smoking probably make their mark.

One of the first things kids used to learn in high school biology is the folly of Lamarckian evolution- the idea that environmental and behavioral forces can shape heredity (ie: that giraffes developed long necks because successive generations kept stretching after higher leaves). Studies like this one from UCLA, however, suggest that Lamarckian thinking may not be totally wrong after all. While no one is claiming that you can pass on your abs of steel to your grandchildren, it does seem increasingly certain that heredity is much more complicated than we thought.

H/T Eureka Alert

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About brainiac Brainiac is the daily blog of the Globe's Sunday Ideas section, covering news and delights from the worlds of art, science, literature, history, design, and more. You can follow us on Twitter @GlobeIdeas.
Brainiac blogger Kevin Hartnett is a writer in Columbia, South Carolina. He can be reached here.

Leon Neyfakh is the staff writer for Ideas. Amanda Katz is the deputy Ideas editor. Stephen Heuser is the Ideas editor.

Guest blogger Simon Waxman is Managing Editor of Boston Review and has written for WBUR, Alternet, McSweeney's, Jacobin, and others.

Guest blogger Elizabeth Manus is a writer living in New York City. She has been a book review editor at the Boston Phoenix, and a columnist for The New York Observer and Metro.

Guest blogger Sarah Laskow is a freelance writer and editor in New York City. She edits Smithsonian's SmartNews blog and has contributed to Salon, Good, The American Prospect, Bloomberg News, and other publications.

Guest blogger Joshua Glenn is a Boston-based writer, publisher, and freelance semiotician. He was the original Brainiac blogger, and is currently editor of the blog HiLobrow, publisher of a series of Radium Age science fiction novels, and co-author/co-editor of several books, including the story collection "Significant Objects" and the kids' field guide to life "Unbored."

Guest blogger Ruth Graham is a freelance journalist in New Hampshire, and a frequent Ideas contributor. She is a former features editor for the New York Sun, and has written for publications including Slate and the Wall Street Journal.

Joshua Rothman is a graduate student and Teaching Fellow in the Harvard English department, and an Instructor in Public Policy at the Harvard Kennedy School of Government. He teaches novels and political writing.


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