Like people, caribou are individuals. Each animal has a different colouration pattern, size, metabolism and other characteristics. And each behaves differently, including in specific environments. But what drives such differences, or diversity, in caribou? Are such mechanisms similar in other animals, including people? And can understanding what gives rise to such diversity help conserve caribou, a threatened species in Canada, which recently became functionally extinct in the Lower 48 US? This study has identified a natural mechanism in caribou that preserves and ensures long-term genetic and behavioural diversity of the species in various habitats across western North America, from Alaska to the Southern Canadian Rockies. This mechanism, called “balancing selection,” has resulted in caribou populations having not only distinctly different genetic traits but also diverse and likely adaptive behaviours, including whether individual animals migrate or not. Balancing selection could ensure that two or more behaviours or characteristics are selected at the same time, by balancing the benefits of one type of behaviour or appearance with the benefits of other types. This research is the first genomic study of caribou and perhaps the first to confirm the gene-driven balancing selection mechanism in a wild species in nature. – Marco Musiani

Cavedon, M., Gubili, C., Heppenheimer, E., vonHoldt, B., Mariani, S., Hebblewhite, M., … Musiani, M. (2019). Genomics, environment and balancing selection in behaviourally bimodal populations: The caribou case. Molecular Ecology, 28(8), 1946–1963.https://doi.org/10.1111/mec.15039