This article analyzes the evolutionary genesis of the aldehyde dehydrogenase 2 (ALDH2) mutation in East Asia through the lenses of institutional economics and systems sociology. While biology typically frames the absence of alcohol tolerance as a metabolic defect, this paper proposes the concept of functional redundancy. We argue that the specific social organization of rice societies—characterized by deep material interdependence—rendered alcohol consumption superfluous as an instrument for trust-building and social cohesion. The resulting genetic path dependency illustrates how historical institutional frameworks continue to shape the biological constitution of modern populations.