This film explores the genetics and evolution of lactase persistence in humans.

Babies can easily digest milk, the food especially provided for them by their mothers. Later in life, most of us lose this ability because we stop producing lactase, the enzyme that helps us digest the sugar in milk. But about one-third of adults worldwide continue to produce the enzyme, a phenomenon known as lactase persistence. This film explores the genetics behind lactase persistence and discusses research that traces the origin of this trait to less than 10,000 years ago. The origin of lactase persistence coincides with a cultural shift in human populations who began to use the milk of other mammals as food. Combining genetics, chemistry, and anthropology, this story provides a compelling example of the co-evolution of human gene regulation and human culture.

The “Abbreviated Film Guide” provides a short summary of the film, along with key concepts and connections to curriculum standards.

An audio descriptive version of the film is available via our media player.