Formation of a specific partner preference in female prairie voles involves changes in their gene structure that do not alter the DNA sequence, but influence genetic expression, reports a study published this week in Nature Neuroscience. These so-called epigenetic changes occur following mating, which is known to cause lifelong pair-bonding in prairie voles, a socially monogamous species.
Mohamed Kabbaj and colleagues were able to trigger pair-bonding in female voles even in the absence of mating using a drug, Trichostatin A (TSA), that causes changes in their histone proteins, which act as spools to condense DNA in cells. These epigenetic changes involving the histones occurred specifically in genes encoding receptors for the hormones oxytocin and vasopressin, which are known to be involved in partner preference and social behavior in general.Female voles on TSA had increased levels of oxytocin and vasopressin receptors in their brains. Kabbaj and colleagues found that drugs that block these receptors prevented pair-bonding.
These findings demonstrate that epigenetic changes are involved in formation of social bonds in prairie voles, and suggest that similar changes may be involved in other types of social behaviors in other species as well.