Epigenetics is one of the latest fads in biology. It arises out of evo-devo and its proponents tell us that epigenetics will transform the way we think about evolution. I've been trying to understand this phenomenon starting with some simple questions about what, exactly, is so new. I'd be happy if someone could just explain what they mean by "epigenetics" [Epigenetics in New Scientist, Epigenetics Revisited, Epigenetics, Epigenetics Again].
Eva Jablonka is a Professor at the Cohn Institute for the History and Philosophy of Science and Ideas at Tel-Aviv University (Israel). Jablonka was one of the 16 people who met in Alterberg, Austria last summer to discuss the faults in modern evolutionary biology. She writes an article entitled "Extending Darwinism" in the latest issue of SEED magazine.
I and several other biologists believe the MS [Modern Synthesis1] is in need of serious revision. Growing evidence indicated that there is more to heredity than DNA, that heritable non-DNA variations can take place during development, sometimes in response to an organism's environment. The notion of soft inheritance is returning to reputable scientific inquiry. Moreover, there seem to be cellular mechanisms activated during periods of extreme stress that trigger bursts of genetic and non-genetic heritable variations, inducing rapid evolutionary change. These realizations promise to profoundly alter our view of evolutionary dynamics.Nothing new here, folks. It's just the same old gibberish that we've been hearing for the past several years.
If there is as much natural variation induced by environmental factors as lab studies suggest, then rapid evolutionary change could occur without any genetic change at all.
But there is one thing that's worth noting. Eva Jablonka has done what few of her fellow epigeneticists have attempted. She defines what she means by epigenetics!
Epigenetics is a term that includes all the processes underlying developmental flexibility and stability, and epigenetic inheritance is part of this. Epigenetic inheritance is the transmission of developmental variations that have nothing to do with changes in the DNA base sequences. In its broad sense, it covers the transmission of any differences that do not depend on gene differences, so it encompasses the cultural inheritance of different religious beliefs in humans and song dialects in birds. It even includes the developmental legacies that a young mammal may receive from its mother through her placenta or milk—transmitted antibodies, for example, or chemical traces that tell the youngsters what the mother has been eating and, therefore, what they should eat.Yes, but does it include the kitchen sink?
The good thing about incorporating these things into evolutionary theory is that it solves the problem of creationism. As long as creationism is passed on from parent to child then it becomes part of evolution. Isn't that cool?
1. Her version of the Modern Synthesis only includes natural selection.