Lactase persistence is the continued activity of the enzyme lactase in adulthood. Since lactase's only function is the digestion of lactose in milk, in most mammals species the activity of the enzyme is dramatically reduced after weaning. However in some human populations lactase persistence has recently evolved as an adaptation to the consumption of non-human milk and dairy products beyond infancy. The majority of people around the world remain lactase non-persistent, and consequently are affected by varying degrees of lactose intolerance as adults – though not all genetically lactase non-persistent individuals are noticeably lactose intolerant, and not all lactose intolerant individuals have the lactase non-persistence allele.
Famous quotes containing the word persistence:
“Nothing in the world can take the place of Persistence. Talent will not; nothing is more common than unsuccessful men with talent. Genius will not; unrewarded genius is almost a proverb. Education will not; the world is full of educated derelicts. Persistence and Determination alone are omnipotent. The slogan Press On, has solved and will always solve the problems of the human race.”
—Calvin Coolidge (18721933)