From one person to another, or one mouse strain to another, there is substantial variation in individual reporting of pain intensity and frequency as well as in behaviors indicative of pain.  Genetics are responsible for some of this variability: some people inherit genetic mutations that drastically affect the protein made by the gene and make them unable to feel pain, or mutations that make them suffer from pain chronically. More subtly, people also inherit single nucleotide polymorphisms—individual differences in just one of the molecules that make up our DNA—which may result in moderate alterations in the structure of the protein produced and make them more or less sensitive to something painful or more or less susceptible to chronic pain. While historically, the field of pain genetics has concerned itself primarily with rare pain conditions resulting from inheritance of a single gene, the past few years have been characterized by significant progress in our understanding of the genetic contributions to “common” pain as a result of new methodologies including the genome-wide genotyping approach.  The most recent findings in the genetics of pain are summarized and the potential applications of these findings to human health are discussed in our review paper.  (By Erin Young, http://jmg.bmj.com/content/early/2011/11/05/jmedgenet-2011-100386.abstract?papetoc )