March 15th, 2021
Studying the evolution of lactose tolerance, scientifically called lactase persistence, we can see how cultural development and genetic adaptations can evolve together.
Generally speaking, the ability to digest dairy disappears as humans approach adulthood. Lactase is the enzyme responsible for allowing the body to digest milk fully. Without it, we show symptoms of lactose intolerance: nausea, bloating, and stomach cramps, to name a few.
However, some populations have developed a genetic mutation called lactase persistence, allowing adults to keep digesting dairy into adulthood. There is one primary mutation in Europeans, but in different populations throughout Africa, there are as many as four! Why? How were ancient Africans able to keep drinking milk when their bodies stopped producing lactase? Scientists now think that ancient African cultures learned that by fermenting milk and creating yogurt, they could eat dairy without the symptoms of lactose intolerance. Little did they know that by fermenting the milk, they were naturally reducing the lactase present, making it easier to digest.
These studies provide a glimpse into not only the history of dairy farming and the evolution of the agricultural society, but it gives insight into the determination of the human spirit, both culturally and genetically, to adapt to a changing environment.