The Koala genome provides insights into adaptation and conservation

Recently published in the prestigious journal Nature Genetics is another marsupial genome, this time it is the iconic koala, a superb effort by a diverse team of specialists including Marilyn.

The paper was highlighted by a cover picture on the printed journal and a commentary by Darren J Burgess in the journal: 2018 Sep;19(9):533. doi: 10.1038/s41576-018-0039-5.

At least in the northern half of Australia, koala populations are ‘vulnerable’ due to habitat loss and widespread disease. The team sequenced the koala genome, producing a complete and contiguous marsupial reference genome, including centromeres, a notoriously difficult region. Among the discoveries is a proliferation of cytochrome P450 genes. These code for enzymes that can detoxify plant toxins, allowing them to survive on a harsh diet of eucalypt leaves.Koalas’ ability to smell, taste and moderate ingestion of plant secondary metabolites may be due to expansions in the vomeronasal and taste receptors. The team identified novel milk proteins that protect young in the pouch and annotated immune genes important for response to chlamydial disease. Historical demography showed a substantial population crash coincident with the decline of Australian megafauna, while contemporary populations had biogeographic boundaries and increased inbreeding in populations affected by historic translocations. A key finding was  identification of genetically diverse populations that require habitat corridors and instituting of translocation programs to aid the koala’s survival in the wild.