Adaptation and conservation insights from the koala genome

The koala is the only extant species of the marsupial family Phascolarctidae and is now classified as ‘vulnerable’ due to habitat loss and widespread disease. We sequenced the koala genome, producing the most complete and contiguous marsupial reference genome to date. We show that the koala’s ability to detoxify eucalypt foliage, toxic to most other mammals, may be due to expansions within a Cytochrome P450 gene family, and its ability to smell, taste, and moderate ingestion of plant secondary metabolites, may be due to expansions in the vomeronasal and taste receptors. We characterised centromeres and novel lactation proteins that protect young in the pouch, as well as immune responses to chlamydial disease. Historical demography revealed a significant population crash coincident with the decline of Australian megafauna, while contemporary populations revealed biogeographic boundaries and increased inbreeding in populations impacted by historic translocations. Genetically diverse populations requiring habitat corridors and translocation programs were identified and provide the key to the koala’s survival in the wild.