Cross-posted from Denim and Tweed.
It is a widespread misconception that, as we developed the technology to reshape our environment to our preferences, human beings neutralized the power of natural selection. Quite the opposite is true: some of the best-known examples of recent evolutionary change in humans are attributable to technology. People who colonized high-altitude environments were selected for tolerance of low-oxygen conditions in the high Himalayas and Andes; populations that have historically raised cattle for milk evolved the ability to digest milk sugars as adults.
A recent study of population genetics in Native American groups suggests that another example is ripening in the experimental fields just a few blocks away from my office at the University of Minnesota: Corn, or maize, may have exerted natural selection on the human populations that first cultivated it.
The target of this new study is an allele called 230Cys, a variant of a gene involved in transporting cholesterol. 230Cys is known only in Native American populations, and it’s associated with abnormally low production of HDL cholesterol (that’s the “good” kind of cholesterol) and thereby increased risk for obesity, diabetes, and heart disease. In Native American populations, the genetic code near 230Cys shows the reduced diversity associated with a selective sweep, which suggests that, although it’s not particuarly helpful now, this variant may have been favored by selection in the past.