Anthropological and genetic studies analyzing blood group distributions among indigenous populations worldwide consistently show a remarkably high prevalence of Blood Type O. In many indigenous groups across the Americas, the Pacific, and parts of Australia, the frequency of Type O approaches near-fixation or absolute dominance due to historical population bottlenecks, founder effects, and genetic drift over thousands of years. Conversely, types A, B, and AB appear in much lower frequencies or are entirely absent in certain isolated native communities, reflecting distinct ancestral heritage patterns.