Vasopressin and Titillating Lives of Voles

One of the cutest bits of research I’ve collected on sexual behavior and genetics has to be that regarding the vole (1-3).

Seems the typically prairie vole (Microtus ochrogaster) is a paragon of puritan chastity. They find a mate and that’s it; they’re dedicated husbands and fathers.

Not like that slutty meadow vole (Microtus pennsylvanicus). Seems the meadow vole sleeps around, uh huh. They’re generally neglectful of both the wife and kids. I bet they try to blame it on “selection pressure” due to the "vast" difference between prairie and meadow environments, or the way they were raised. Whatever, we all know they have vole free agency.

But it turns out prarie voles generally have longer microsatellites (“genetic stutters, usually just two or four bases long”) near the encoding region for a receptor for vasopressin, causing them to take in more of the hormone. Researchers have even been able to take the licentious meadow voles and, using a viral vector, alter their genes to increase the number of these receptors. The voles are thus converted into faithful mates.

It’s an injection for mortality ;-). Would you take it?

Studying humans is far more difficult, not to mention controversial; no one will be altering our genes in a double blind study to see if we abandon our illicit trysts. Furthermore, a possible mechanism in humans for such would likely be more complicated. But this same hormone has been found to play a role in autism, which is well known for it’s social limitations, and a similar microsatellite has been found to be far shorter in chimps than in humans, but near the same size for the more social and gregarious bonobos.

No, it’s not highly relevant to homosexuality, not near other studies I could (and have and will :-)) reference. But it’s one of my favorites, something about the cute vole I guess.

It is a striking effect on sexual and familial behavior, though, and it does make one wonder. If your justice involves punishing people for their “free will” choices, instead of controlling already constrained human will by presenting additional consequences, what happens if people are found to make all their choices for a reason?

Also, let me add to this long held post, I’m posting this today as it was brought to mind by the post on monogamy by Mark, here. Personally I feel monogamy is as right for me as homosexuality. I check my innate self and it reports back the same: I’m a gay prairie vole ;-). As I wrote there, I can’t really say monogamy is a righteous thing that I cling to in a noble act of self-sacrifice. It’s not; it’s what I want, something in which I find great value. I’ve no ethical problem with my meadow vole cousins—clearly there’s a pressure to keep both of us in the population. I’ve no problem with sex as long as it’s not used to hurt the other voles :-).

References:
1. Lim, M. M., Z. Wang, et al. (2004). "Enhanced partner preference in a promiscuous species by manipulating the expression of a single gene." Nature 429: 754-757.
2. Hammock, E. A. D. and L. J. Young (2005). "Microsatellite Instability Generates Diversity in Brain and Sociobehavioral Traits." Science 2005(308): 1630-1634.
3. Pennisi, E. (2005). "In Voles, a Little Extra DNA Makes for Faithful Mates." Science 308: 1533.