Asian Enzyme ’Defect’ Could Have Emerged as Evolutionary Advantage

The genetic mutation that causes alcohol intolerance among some East Asians may have arisen as a protection against alcoholism dating to the period when rice was first cultivated, Time magazine reported Jan. 20.

Researchers who studied the DNA of 38 Asian populations exhibiting the mutation that affects the enzyme ALDH-2 — which helps metabolize alcohol — found a correlation between development of the mutation and initiation of rice cultivation up to 10,000 years ago. The study authors speculated that the mutation developed to allow early rice farmers to enjoy the beneficial uses of fermented rice — as a preservative, for example — while protecting against immoderate alcohol consumption.

The study appears in the journal BMC Evolutionary Biology.