GRANDMA'S CURSE

Linda Joyce Beck, mountain explorer

The Economist really is an excellent news magazine.  Not only does it discuss important matters from all over the world, often in an amusingly cynical way, it also publish interesting stories about medicine (as well as books, science in general, and other such matters).  For instance, in the November 9^th issue, on page 82, there is a short article you all should read*.  Its title is “Grandma’s Curse”.

Seems some scientists working in Los Angeles have discovered something important and very surprising about smoking rats.  Actually, the rats themselves didn’t smoke; rather the researchers, headed by one Dr. Virender Rehan, took pregnant mother rats and smeared them with nicotine.  Then they observed the outcome.  As was expected and well understood, baby mice from the F1 generation all showed smoking-related asthma-like symptoms.  Why not ? – they were developing when their mothers were dosed.  The surprising observation  made by Dr. Rehan and his colleagues was that even baby rats of the F2 generation displayed the same symptoms.  This was unexpected because neither these baby rats nor their mothers had been directly subjected to nicotine.  Obviously, Rehan is waiting eagerly for the F2 ratlets to grow old enough to produce an F3 generation.  If they, too, show the symptoms of smoking a Nobel awaits.

What this experiment seems to show is that these rats were capable of inheriting an acquired characteristic.  Inheritance of acquired characteristics – Lamarckian evolution – supposedly  was exploded by Darwin.  Francis Crick, famous co-discoverer of the DNA double helix, also is well known for denying the possibility of genetic information becoming modified by the environment or experience (baring mutations, of course.)  So Dr. Rehan is proposing that it is not the rat DNA that is being modified, but rather things they call “epigenetic factors”.  I don’t really understand epigenetic factors.  However, it seems that stuff secreted by the mother and placed into the egg influences the early development of the embryo in an all-important way.  The guess is that nicotine inhibits the activity of one or more of these “maternal determinants” – although I still fail to understand how this extends to the F2 generation.  I await enlightenment.

If you want to see the original article, go to Google Scholar, type in Virender Rehan,  then restrict your search to articles published in 2012.  If you do this and read the article, please explain it to me.

Anyway:  the take away message.  For one more reason, don’t smoke.  Especially if you plan to get pregnant.  Your grandchildren will thank you.

*Or, you can get it on line: http://www.economist.com/news/science-and-technology/21565573-some-effects-smoking-may-be-passed-grandmother