I was thinking about doing a Ten-Word-Tuesday post about being sick (something I ate didn't agree with me), but I'm sure you don't want to hear how often I've been to the bathroom today. So here's a more interesting article from the New York Times about how human culture, long thought to shield us from natural selection and evolution, may actually affect our genes.
Some of the best examples of culture influencing our genetic makeup have to do with what foods we eat, as our genes determine how well we can digest certain types of food. For instance, many adults are unable to digest lactose, a sugar found in milk, because the genes that break it down are no longer active. Populations whose ancestors reared cattle retain the ability to digest milk as adults. Northern Europeans tend to be lactose tolerant, but there are a few groups in Africa who have the same ability. The interesting point is that each group took a different genetic route to arrive at the same cultural destination, implying they evolved this trait independently.
Milk isn't the only food that influences our genes; starch consumption affects how much amylase (a starch-digesting enzyme) people produce. People who live in societies that grow food have more copies of the amylase gene than people who primarily hunt or fish. Diseases may also affect the genes of the immune system. Biologists think up to 10% of our genes may be influenced by selective pressures, though we still have much to learn about the roles of these genes.
So the next time you decide to send a group of humans off to colonize a planet or create aliens for them to encounter, think about what kind of environment they'll be in and what traits they'll need to flourish there. Perhaps humans aboard a generation ship will adapt to space travel, only to have their descendants struggle to survive on a planet. Perhaps they'll evolve so they can eat new types of food, and this change may have other side effects. These situations can tell us something about what we're like here and now.