Prodynorphin is an opioid polypeptide hormone involved with chemical signal transduction and cell communication. Prodynorphin is a basic building block of endorphins, the chemical messengers in the brain that appear most heavily involved in the anticipation and experience of pain (and possibly pleasure – the two pathways are closely interrelated chemically) as well as the formation of deep emotional bonds. Endorphins are also critical in learning and memory.
Prodynorphin levels also seem to be highly correlated with variations in human perception, as well as susceptibility to drug dependence, and is expressed more readily in human beings than in other primates.
In humans a gene causes prodynorphins to produce more prolifically than they do in non-human primates.
In addition, with 98-99% of genetic base material in humans and other primates being close to identical, the section related to prodynorphins differs by as much as 10%, and there are striking differences in the production of prodynorphins from one population of humans to the next.Experimental introduction of human and chimpanzee prodynorphin gene segments into human neural cells saw a dramatic difference in prodynorphin expression; the human version expressed 20% more than the chimpanzee version.
Scientists hypothesize that the extra production of prodynorphin encouraged emotional bonding as well as the development of human intelligence and maybe even language. Many are speculating that prodynorphin may be one of the first genetic markers that truly demonstrates what makes us human.
Excerpted and adapted from: Prodynorphin and Prodynorphin