Gene switches work similarly to light switches in controlling one feature of their environments. Scholars study the Pitx1 gene in a specific type of fish. They learn the different ways this switch controls various body parts and...

Does the human body evolve as quickly as human culture? With a stellar 15-minute video, explore the trait of lactose intolerance. Only about 1/3 of human adults seem to still have the enzyme lactase and therefore, the ability to digest...