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Parental-care puzzle in mice solved by thinking outside the brain
Both parents of oldfield mice care for offspring, whereas in deer mice, mothers usually care for pups. The discovery of a type of adrenal-gland cell that is present in oldfield mice but not in deer mice helps to explain the difference.
How does a species evolve its unique repertoire of behaviours? The identification of causal relationships between genes and biological outcomes is a major goal of biology. Behaviour, an emergent property of the brain, is arguably the most fascinating and challenging puzzle in the quest to connect genes to their consequences — scientists need to find the circuit that mediates the behaviour of interest and then discover where and when in the circuit a given gene acts. Writing in Nature, Niepoth et al.1 reveal that differences in parenting behaviour of mice species can arise, in part, through evolutionary innovation of a type of cell in the adrenal gland, rather than through a change initiated in the brain. These remarkable findings highlight the power of evolutionary comparisons and provide an innovative way to understand how the body can direct behavioural outcomes.