Systematics and Evolution (HA)
Mimosoideae
 Program Leader:
Joe Miller
This research project has two major elements. The first investigates molecular systematics of the genus Acacias.l. and related genera of the Mimosoideae, and the second entails species and population level molecular genetic research on the Mulga species complex, Acacia aneura and relatives. The aim of this work is to produce both scientific articles describing the genetic relationships of the taxa and also to produce web-based plant identification keys and factsheets.
Molecular Systematics of Acacia and allied genera of the Mimosoideae
The plant genus Acacia, with over 1,500 species, consists of shrubs and trees that are dominant in the arid vegetation of the tropical and subtropical world, including the Americas, Africa and Australia. An understanding of the systematics and phylogeny, will clarify questions of species circumscription, relationship, distribution, nomenclature, and ecology. The data sets and resulting phylogeny facilitate investigating questions relating to morphological evolution, patterns of diversification, and biogeography. This work has developed a detailed, well sampled and supported molecular phylogeny of the derived members of the Mimosoideae by sequencing multiple chloroplast loci. This work has found strong support for the segregation of several genera from Acacia that have resulted in several nomenclatural changes. The work is now focuses on relationships within the major lineages specifically the ant acacia containing lineage of the Americas and Africa as well as investigation of phylogenetic relationships among the Australian species. Major collaborators are David Seigler, University of Illinois, Dan Murphy, RBG Melbourne, Gillian Brown, University of Melbourne and Bruce Maslin, Department of Environment and Conservation, Perth.
The Mulga species complex
Acacia aneura and its close relatives form a highly variable species complex commonly known as Mulga. They are small trees that dominate the vegetation of arid regions, in all occupying around 20% of Australia. Our research studies the phenotypic and genetic basis of the more important types variation found in Mulga, especially growth form and phyllode and pod morphology. This variation occurs both between and within populations and often results in a very complex mosaic of mixed Mulga populations. The underlying genetic and biological factors responsible for this variation are being explored and include hybridization, polyploidy, apomixis and neoteny. The major goal of the project is to generate taxonomic and genetic frameworks to better describe and name the phenotypic variation. Major collaborators are Bruce Maslin, Margaret Byrne, Jane Sampson and Jordan Reid of the WA Department of Environment and Conservation, Perth.
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