EPIGENETICS. Two great videos (located together, on the same page)
NOVA | Epigenetics. Environmental factors can alter the ways our genes are expressed, making even identical twins different, 13 minutes, aired, July 24, 2007.
NOVA | The Ghost in the Genes. (Also about Epigenetics.) Watch this fascinating show about how the interplay between environmental factors and our genes. 48 minutes.
