There is increasing focus on the idea of networks that are composed of genes and proteins. Although the complex interplay of macromolecules is a certainty, there is benefit in taking a reductionist approach when envisioning common molecular routes toward disease. Indeed, for many diseases, different genetic loci must impinge on a common pathway to pathogenesis. This means that as a risk allele at a genetic locus comes into focus, it provides clues to other risk loci and mechanisms by which variability at the same locus or on the same pathway can contribute to disease.
