Obesity, type 2 diabetes, hyperlipidaemia, hypertension and liver disease are common metabolic disorders in Mexican Americans, the largest minority population in the US. Mexican Americans are an admixed population with European, Amerindian and African ancestries. Ancestral analysis by genotyping a set of ancestry informative markers (AIMs) in this study identified associations between ancestral components and common metabolic traits in Mexican Americans. These observations highlight the potential of personalized prevention/intervention of common diseases in admixed populations based on quantitative ethnic information. (By HQQ, http://jmg.bmj.com/content/early/2012/06/19/jmedgenet-2012-100966 )