Recent discoveries in molecular biology have shown that genes governing life processes in widely different organisms from yeast to humans are essentially alike. That is the underlying theme of this book as it looks for meaning in the natural world while exploring complex questions in molecular genetics. Ackerman, a former staff writer for National Geographic and a nature author (Notes from the Shore), weaves her own personal experiences into this popular account of the natural history of heredity. (When she is pregnant with her first child, Ackerman worries that the baby will inherit the gene that caused the retardation of her younger sister.) Topics range from development and sex determination to biological clocks and cell death, and more.