Got Lactase? The Co-evolution of Genes and Culture (2013)

Human babies drink milk; it's the food especially provided for them by their mothers. But worldwide, only a third of adults can actually digest lactose, the sugar in milk. In this short film, we follow human geneticist Spencer Wells as he tracks down the genetic changes associated with the ability to digest lactose, tracing the origins of the trait to less than 10,000 years ago, when some human populations started domesticating dairy animals. Combining genetics, chemistry, and anthropology, this story provides a compelling example of the co-evolution of human genes and human culture.