Title

Using microsatellite markers to study dugong phylogeography

Objective

To investigate the intraspecific genetic structure of dugongs along the coast of Queensland using microsatellite markers.

Relevance

Information on the genetic structure of dugong populations provides insights into the appropriate spatial scale for management. The significance of the decline in dugong numbers along the urban coast of the Great Barrier Reef depends on the time scale for recolonisation from adjacent regions. The present information on the genetic structure of dugongs based on amitochondrial DNA marker, suggests a low level of female mediated gene flow between neighbouring populations and indicates that successful recolonisation of a depleted area may be extremely slow. The precise number and boundaries of genetic units along the Australian coast were not well defined by the mitochondrial marker.

Feasibility

Preliminary work by Dr Dani Tikel provides a substantial foundation for the development of microsatellite markers. Parallel work on microsatellite markers for the West Indian manatee (University of Florida) is yielding promising results which should have application to dugongs. When suitable microsatellite markers are developed, they are expected to have two advantages over the mitochondrial markers used to date.

• They may provide finer spatial resolution of the genetic structure of dugongs and insights into their social organisation.
• They will provide information on both male and female mediated gene flow (mitochondrial DNA provides information on females only).

Methodology

Already established is an extensive dugong tissue bank held at James Cook University, as well as a dugong genomic library. Ideally, at least 20 informative loci are required. About 30 clones from the library have screened positive for dinucleotide microsatellites. Six of these microsatellites have been sequenced. This project would involve characterisation of the existing microsatellites to examine if they would be informative for an intraspecific level study of the dugong, and the expansion of the existing genomic library in order to identify additional microsatellite loci. In addition, microsatellite markers developed for West Indian manatees in Florida will be trialed to determine their suitability for dugongs.

Cost

$ 85 000 if done as a PhD project.

$120 000 if done as a post-doctoral project.

Time

Three years if done as a PhD project, two years if done as a post-doctoral project.