Epigenetics; a negative review (Introduction)

by David Turell , Sunday, October 14, 2012, 16:32 (4424 days ago) @ dhw

DAVID: 
> 
> http://online.wsj.com/article/SB10000872396390443294904578048381149899900.html?KEYWORDS... 
> The truth appears to be slightly more positive than Ridley's opinion
> 
> This sounds like an interesting article, but one has to subscribe in order to read it. Perhaps you could summarize Ridley's opinion for us?-His conclusions:-"The evidence to back up such claims is threadbare. Frequently mentioned is a study of a remote Swedish province called Overkalix, which suffered famines whose effects are felt in the health of the second generation of descendants. But the sample size is small, the effects marginal and no specific epigenetic reprogramming has been established as the cause. Evidence from rats is slightly better: One study found energy metabolism in pregnant rats affected by what happened to the parent. But the most famous animal case, involving a mouse's coat color tied to diabetes and obesity, is somewhat unpredictable and untypical.
 
Moreover, beginning a century ago with Wilhelm Johannsen, who coined the word "gene," many experiments have ruled out all but the most trivial Lamarckian effects. These now- forgotten tests involved "pure lines" of genetically identical plants or animals. The variation in pure lines, in weight of beans in bean plants for example, again and again shows no heritability, ruling out heritable nongenetic effects.
 
As Dr. Davey Smith puts it: 'The conclusion from over 100 years of research must be that epigenetic inheritance is not a major contributor' to physical resemblance across generations."