Dunnarts are small nocturnal mouse-sized marsupials endemic to Australia. Nineteen different species are found in habitats ranging from tropical savanna grasslands to desert sandhills and dense forests of Australia’s southeast and southwest. The fat-tailed dunnart (Sminthopsis crassicaudata) belongs to the Dasyuridae family, which also includes the little red kaluta, quolls, and the Tasmanian devil.
Dunnarts sleep during the day in cup-shaped nests of dried grass and leaves in fallen hollow logs or in clumps of grass, sedges and grasstrees. Their diet includes insects such as beetles, spiders, small reptiles, and amphibians. They store fat reserves in their carrot-shaped tail for times of food shortage.
The fat-tailed dunnart can survive in extreme, semi-arid environments. One of the survival techniques that it uses is daily torpor. It lowers its body temperature and metabolic rate [1] in order to reduce energy expenditure. Torpor is unaffected by alterations in photoperiod but is greatly affected by environmental conditions.
The main threats to the dunnart are habitat fragmentation, inappropriate fire regimes, and feral predators. While once common throughout Southwest Australia these diminutive marsupials are near threatened in Victoria and now confined to ‘islands’ of remnant vegetation, the result of large-scale clearing for agriculture.
The majority of its remaining habitat is privately-owned bush remnants. Dunnarts are known to be able to recolonise burnt areas readily as they are adapted to mid-successional complexes of vegetation. However, a single fire can potentially wipe out an entire population.
DNA Zoo joined forces with Prof Andrew Pask and Dr Stephen Frankenberg from University of Melbourne, Australia to deliver a much required genomic resource: a chromosome-length genome assembly for the fat-tailed dunnart. The assembly is based on the draft provided by the University of Melbourne team, led by Prof Andrew Pask. The effort has been supported by an ARC grant (DP160103683) to Pask and Frankenberg and Oz Mammals Genomics initiative, a Bioplatforms Australia framework initiative, building genomic resources for conservation through a thorough understanding of the evolution of Australia’s unique mammals that are now under threat, through climate, disease or habitat modifications.
This draft assembly was scaffolded with 548,133,068 PE Hi-C reads generated by DNA Zoo labs using 3D-DNA (Dudchenko et al., 2017) and Juicebox Assembly Tools (Dudchenko et al., 2018). See our Methods page for more details! The Hi-C work was supported by resources provided by DNA Zoo Australia, The University of Western Australia and DNA Zoo, Aiden Lab at Baylor College of Medicine with additional computational resources and support from the Pawsey Supercomputing Centre with funding from the Australian Government, the Government of Western Australia.
The following people contributed to the Hi-C chromosome-length upgrade of the project: Erez Aiden, Olga Dudchenko, Ashling Charles & Parwinder Kaur.
Citations
1. Warnecke, Lisa; James Turner; Fritz Geiser (2008). "Torpor and basking in a small arid zone marsupial". Naturwissenschaften. 95 (1): 73–78. doi:10.1007/s00114-007-0293-4.