Chasing Mendel: five questions for personalized medicine.

Ideas about personalized medicine are underpinned in part by evolutionary biology's Modern Synthesis. In this essay we link personalized medicine to the efforts of the early statistical investigators who quantified the heritability of human phenotype and then attempted to reconcile their observations with Mendelian genetics. As information about the heritability of common diseases was obtained, similar efforts were directed at understanding the genetic basis of disease phenotypes. These ideas were part of the rationale driving the Human Genome Project and subsequently the personalized medicine movement. In this context, we discuss: (1) the current state of the genotype-phenotype relationship in humans, (2) the common-disease-common-variant hypothesis, (3) the current ability of 'omic' information to inform clinical decision making, (4) emerging ideas about the therapeutic insight available from rare genetic variants, and (5) the social and behavioural barriers to the wider potential success of personalized medicine. There are significant gaps in knowledge as well as conceptual, intellectual, and philosophical limitations in each of these five areas. We then provide specific recommendations to mitigate these limitations and close by asking if it is time for the biomedical research community to 'stop chasing Mendel?'