Poster Annual Conference of the Genetics Society of Australasia with the NZ Society for Biochemistry & Molecular Biology

Inbreeding on the rise: Molecular-based pedigree reveals an early warning sign of gene diversity loss in an island population of Tasmanian devils (Sarcophilus harrisii) (777)

Elspeth A McLennan 1 , Rebecca M Gooley 1 , Phil Wise 2 , Katherine Belov 1 , Carolyn J Hogg 1 , Catherine E Grueber 1
  1. The University of Sydney, Camperdown, Sydney, NSW, Australia
  2. Save the Tasmanian Devil Program, Department of Primary Industries, Parks, Water and Environment, Hobart, TAS, Australia

Tasmanian devils have experienced an 85% population decline since the emergence of an infectious cancer, devil facial tumour disease (DFTD). In response, a captive insurance population was established in 2006 with a subpopulation later introduced onto Maria Island, Tasmania. The aim of our study was to 1) examine the genetic parameters of the Maria Island population as a stand-alone site and within its broader metapopulation context, 2) give evidence on the efficacy of assisted colonisations, and 3) inform future translocation events. We reconstructed the pedigree of 86 island-born devils using 31 polymorphic microsatellite loci. We used a combination of molecular and pedigree analysis to monitor change in population genetic parameters since colonisation. Molecular analysis alone revealed no significant change in genetic diversity over the four years of occupation on Maria Island. In contrast, DNA-reconstructed pedigree analysis revealed a statistically significant increase in inbreeding over time due to skewed founder representation. Pedigree modelling predicted that gene diversity would only be maintained above the threshold of 95% for a further 2 years, dropping to 77.1% after 40 years. Modelling of alternative supplementation strategies revealed that introducing eight new founders every three years will enable the population to retain 95% gene diversity until 2056. Our study highlights the value of combining pedigree analyses with molecular data, from both a single-site and metapopulation viewpoint, for analysing changes in genetic parameters within populations of conservation concern. Further, we emphasise the importance of post-release genetic monitoring in an established population, given how quickly inbreeding can accumulate and gene diversity be lost.