Yes, sometimes the size, shape, and condition of a piano dictate what a pianist can do with it. It’s tough to play a concerto on an eighteen-key toy piano, and it’s mighty hard to make beautiful music on an instrument that hasn’t been tuned in fifty years. Likewise, the genome certainly dictates what the epigenome can do. A caterpillar can’t become a human being, but it can become a butterfly by virtue of changes in epigenetic expression that occur during metamorphosis, even though its genome never changes. Similarly, the child of two parents from a long line of people with black hair and
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