Pair-bonding in monogamous prairie voles (Microtus ochrogaster, pictured) is linked to chemical modifications of DNA-packaging proteins in the animals' brains.
Zuoxin Wang, Mohamed Kabbaj and their team at Florida State University in Tallahassee studied the brain chemistry of females as they interacted with males. The researchers focused on enzymes that coordinate epigenetic marks on histones, the protein complexes that coil up DNA and regulate gene expression. Females injected with an inhibitor of these enzymes developed a stronger preference for a random male that had been previously placed in their cage than females not injected with the inhibitor. The inhibitor boosted production of receptors for two hormones linked to sexual and maternal behaviours; similar changes are caused by mating.
The authors say these findings are the first to pair the chemistry of coupling with histone regulation.
Nature Neurosci. http://dx.doi.org/10.1038/nn.3420 (2013)
For a longer story on this research, see go.nature.com/fwah2e