Modern Human Variation: Distribution of Blood Types

"These patterns of ABO and Diego blood type distributions are not similar to those for skin color or other so-called "racial" traits. The implication is that the specific causes responsible for the distribution of human blood types have been different than those for other traits that have been commonly employed to categorize people into "races." Since it would be possible to divide up humanity into radically different groupings using blood typing instead of other genetically inherited traits such as skin color, we have more conclusive evidence that the commonly used typological model for understanding human variation is scientifically unsound."