When I think of epigenetic, I find the piano metaphor helpful. That is, think of your genes as the piano keyboard, specific and well defined. Think of epigenetics as how your piano is played. This is certainly impacted by your environment, especially your home growing up.
The piano metaphor by David Klinghoffer:
“It is as if a piano were being played by a skilled and sensitive musician — say, an improvisational jazz pianist — with the instrument itself responding to his touch not as the expression of an algorithm but of its own life force. There is a very minimal musical score, in the form of DNA, inadequate to describe the music being performed, and then there is the pianist himself engaged in an improvisation on a swiftly shifting suite of themes. And this is only the construction of proteins we’re talking about. It leaves out of the picture entirely the higher-level components — tissues, organs, the whole body plan that draws all the lower-level stuff together into a coherent, functioning form. What we should really be talking about is not a lone piano but a vast orchestra under the directing guidance of an unknown conductor fulfilling an artistic vision, organizing and transcending the music of the assembly of individual players.”
I do like this metaphor, and think of it often in context of human behavior and the “nature v nurture” argument. I believe Robert Sapolsky would agree. That is, of the great influence of the environment to impact how our genes are expressed via epigenetic stimulus.
The one part I don’t buy is the “unknown conductor,” at least in the context of intelligent design. I do believe the epigenetics is the expression of our environment. The metaphorical conductor is the environment itself, the application of which is characterized by chance and environmental support. Environmental support often includes parents, families, schools, faith communities, etc. As related to my article, The Four Scales Of Human Resilience, the resilience outcome is the result of an epigenetic process. The expression of gene’s via epigenetics is like a constraint optimization problem. Where the objective is for genetic survival, subject to, the environment and the fixed coding of the existing genome.
In Samuel Butler’s book Unconscious Memory, he wrote
“that the component cells of our bodies unite to form our single individuality, of which it is not likely they have a conception, and with which they have probably only the same partial and imperfect sympathy as we, the body corporate, have with them.”
Richard Dawkins, in his book The Selfish Gene, does not adddress epigenetics directly, though I think he would certainly agree with the concept. To wit, when discussing female hymenoptera, a kind of insect, he says,
“Whether a female develops into a worker or a queen depends not on her genes but on how she is brought up. That is to say, each female has a complete set of queen-making genes, and a complete set of worker-making genes (or, rather, sets of genes for making each specialized caste of worker, soldier, etc.). Which set of genes is turned on' depends on how the female is reared, in particular on the food she receives.”
