But that does not explain why epigenetic markers are passed on to subsequent generations. How do the markers know what the environmental circumstances of a third generation offspring are going to be?
But why would the response skip a generation?
I don't know if it's an allele. I just saw a Nova special called, "Ghost in our Genes". It explained epigenomes, which I never knew about. It was a fascinating program, which displayed the power of markers to turn genes on and off. It also has disturbing implications, such as is it possible to create a chemical that produces markers that would make genes turn off and give you a dread disease. The possibilities for chemical warfare are frightening.
But why would the response skip a generation?