Steven M. Phelps in Nature:
One of the most pressing questions facing biologists is how variation in the genome is translated into variation in complex traits. Perhaps no trait is more complex or more interesting than social behaviour. How do genomic differences influence aggression, courtship or bonding? Few studies have asked. In a paper online in Nature, Bendesky et al.1 combine genetic crosses, detailed behavioural assays and the latest neuroscience tools to understand species differences in parental care in mice of the genus Peromyscus.
Peromyscus is a diverse North American genus, whose habitats range from arid deserts to montane cloud forests2. Along with these tremendously disparate habitats come comparably variable behaviours. For example, sharing of parental care and social monogamy are rare traits in mammals, but they have evolved at least twice in Peromyscus3. Oldfield mice (P. polionotus), for instance, live in sandy habitats at low population densities, and seem to have adapted to their sparse environments by forming pair bonds, with both sexes providing ample parental care (Fig. 1). By contrast, the deer mouse (P. maniculatus) is tremendously widespread and has a promiscuous mating system similar to that found in many other rodents3. Deer mice provide less parental care than do oldfield mice, with this difference being particularly pronounced in fathers.