We’ve been studying the prairie voles and comparing those to the non-monogamous and asocial Montane and meadow voles to try to get an idea of what are the physiological differences that would be responsible for this behavior. One difference that we thought might be is that prairie voles would have more oxytocin and more vasopressin than Montane [voles]. That turns out to not be the case. The real difference between the two species is the location and quantity of the receptors that respond to it. A neuropeptide is sort of like a key; a key doesn’t do anything unless it goes into a lock, and the lock is like a receptor. If you look in the brain of where those locks are or where those receptors are, you see a big difference between the ones who are monogamous and the ones who are not. Prairie voles for example have high levels of these receptors in reward areas of the brain, whereas the non-monogamous species don’t. We’ve also been looking at the genetic basis of that; why are the receptors in different places? We’ve identified the gene that encodes for the receptor for vasopressin, and actually found a region in the gene, just upstream of the gene in a part of the gene called a promoter, that determines where it’s expressed. We find that there’s variation in the link of an element in that promoter whereby prairie voles who have longer stretches of this sequence have more receptors than prairie voles who have shorter stretches of that sequence. Not only did they have more receptors, but they are more likely to bond, they are more likely to be better fathers and they are more likely to engage other individuals socially. So here’s an example of where a stretch of DNA, a stretch of nucleotides (A, G, C and Ts) can vary across individuals that can really produce a striking difference in their social behavioral traits. I think that this is an exciting finding that really makes the link between genes, the brain and behavior.

social, socialization, prairie, voles, meadow. Montane, monogamous, neuropeptide, receptors, oxytocin, vasopressin, larry, young