The EDAR gene encodes the ectodysplasin A receptor, a member of the tumor necrosis factor receptor family. As this protein is required for the development of hair, teeth, and other ectodermal derivatives, mutations can result in both autosomal dominant and recessive forms of ectodermal dysplasia.Wikipedia
At least one particular SNP in the EDAR gene is also notable for having apparently experienced strong natural selection pressure in a large population, based on the analysis of over 3 million polymorphisms from the International HapMap Project Phase 2. More specifically, both the EDAR and EDA2R genes are involved in a common biologic process, hair development, and both have undergone positive selection in Asians. The canonical SNP in EDAR for this is rs3827760.