Pharmacogenetics: more than skin deep

It is well known that the efficacy of certain drugs varies from individual to individual, depending in part on variation in the genes that encode drug metabolizing enzymes. Whereas ethnic and geographic differences are commonly used to classify drug response, new results show that more accurate and robust genetic clusters-identified by genotyping a modest number of neutral markers-can be inferred with no prior knowledge of ethnicity. Such an approach may eventually become a part of drug evaluation and clinical practice.