Ghost in Your Genes

This episode of NOVA (originally produced and broadcast by the BBC) begins with a puzzling question: why do some twins develop serious diseases while their genetically identical siblings do not? The answer lies in the hugely important discovery of the epigenome, a second genetic code that overlays the body's DNA blueprint and controls how our genes express themselves, with specific portions of the code switching on or off to determine our overall genetic health. Combining expert testimony with easy-to-follow graphics that illustrate the inner workings of our genetic codes, the program points out how environmental conditions (such as drought and famine) can determine the genetic sturdiness or vulnerability of subsequent generations; how personal habits and external conditions (smoking, drugs, stress, etc.) can effect our genetic health and that of our descendants; and how these new discoveries may help us to isolate and eliminate diseases and conditions that have plagued humankind for millennia. True to its title, this is a ghost story—since much of the epigenome's function and purpose remains shrouded in mystery—but one in which the specter offers the promise of substantial scientific breakthroughs. Highly recommended. Aud: H, C, P. (J. Shannon)