“What do we inherit, and how, and why? The relatively new field of epigenetics studies the impact of environment and experience on genes themselves. How much had the gene pool of the Waldens - that apparently cheerful extended family I had seen singing on YouTube - formed me? I did not come from the line of small, wiry, dark-eyed people of the shtetl, the men swaying over crumbling tombstones, prayer books in their hands. The imprint of pogroms, of the difficulties and sorrows of immigrant life was not mine - at least not in the physical sense. But I had carried these things a long way in my heart. I was of that dusty and doomed Polish village - and I was not. What had I inherited psychologically? What was in my blood? I was made of three people: my mother, my father, Ben Walden. Disparate worlds had been floating and colliding within me all my life.”