Hybridization as a tool for rescuing threatened populations


Natasja Noer, Aalborg Universitet

Project leaders: Dr Andrew Weeks and Professor Ary
Hoffmann, University of Melbourne


Many threatened species exists in small isolated populations with low genetic diversity and consequently suffers from  inbreeding depression and low adaptive potential to environmental changes. Once genetic diversity is lost it will take millions of years to recover due to slow mutation rates and inert removal of fixed deleterious alleles in the population. Eventually, many of these populations will go extinct. An approach to tackle this problem is to introduce genes from a genetically distinct population while increasing the population size. This will supply the population with new genetic material that selection can act on and prevent expression of deleterious recessive mutations. The Eastern Barred Bandicoot (Perameles gunnii) used to be widespread across Victoria’s grasslands where its foraging behavior promoted growth of native grass species and wildflowers. At present, the species is nearly extinct due to agriculture and invasive predators and the few survivors are protected in a conservation reserve. The local population is destined for extinction if no actions are taken. In order to prevent this loss and improve genetic diversity of the population, a rescue program has been established in which healthy male bandicoots from a Tasmanian population are mated to Victorian females. This project aims to monitor the genetic status of the population, using high density SNP markers, and ensure that genomes of the Tasmanian population will not dominate the Victorian population, but become an integrated part of the genomes. Thereby, unique genotypes important for local adaptation will be maintained while
fitness is increased.