Oxytocin and vasopressin in human sociality and social psychopathologies

Introduction: Gene Robinson has coined the term “socio-genomics” to describe the genetic basis for social life (Robinson et al., 2005) across diverse animal taxa. The main aim of sociogenomics is to understand the complex pathways by which genes contribute to the wiring of social behavior. Since many animals display varying degrees of social behavior, the evolution and selection of genes that foster such behavior is of considerable interest and the identification of such genes has become a fascinating area of research leveraging on the increasing power of cutting-edge genomic tools. Interestingly, the evolution of large primate brain size has been attributed to the need for “Machiavellian intelligence” to enable individuals to successfully manipulate and engage in group living. It appears that the technology of social networking evidenced today in human society by Facebook and Twitter had its origins early on in the more ancient carbon-based neocortex. Although it is clear that genes encode many aspects of social behavior also in humans (Ebstein et al., 2010), how complex human social behaviors may drive gene evolution is less well understood. A good example of this concept is provided by the domestication of cattle in the Neolithic and how this change in life style impacted human gene selection by extending beyond weaning lactose tolerance in some European populations (Burger et al., 2007). Lactase (the enzyme that breaks down lactose) persistence is a dominant Mendelian trait and the absence of this mutation in early European farmers argues for the “culture-historical hypothesis,” whereby lactase persistence alleles were rare until the advent of dairying early in the Neolithic but then rose rapidly in frequency under natural selection. One wonders if the advent of the age of social networking that appears to be a major preoccupation of a large proportion of the population in developed countries, might not have an evolutionary edge by selecting for some kinds of “twitter” genes.