What is the meaning of this difference between how whites and blacks metabolize sugars (carbohydrates)? Why do these differences exist? The answer may lie far back in history, in a time when these races were not living in the same country or environment.

The researchers suggest that the apparent inhibition of glucose metabolism in blacks may be a reflection of an environment where food was scarce or that the diet was significantly different to that consumed by whites. "In essence, although African populations moved geographically as they came to the United States, their genes retained a pattern more suited to their ancestor's home, becoming maladaptive as African populations adopted a Western diet," Patterson explained.

Although the finding may be controversial, it's not the first time that researchers have found that geographic ancestry predicts genetic variations, he adds. "For example, G6PD deficiency, an inherited disorder that affects red blood cells and is most common in African-American males, is believed to have evolved in some populations as a protection against malaria."

"This study raises the question, are there other examples of groups of gene changes that might be protective under some environments or nutritional scenarios, and maladaptive under others? The practical value of this is providing a tool for looking for these sorts of things. If we really are going to be serious about personalized medicine, we can't ignore the value of this type of knowledge," Patterson said.

Source: University of North Carolina at Chapel Hill School of Medicine