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EVOLUTIONARY BIOLOGY UNIT

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Current research programs:

Our research programs are organised into two major themes:

1) Systematics, Biogeography, Organismal and Character Evolution of the Australasian Fauna

This program provides the systematic framework from which to interpret:

• the historical component to the distribution of organisms, i.e. biogeography

• comparative analyses of the evolution of individual characters, i.e. macroevolution or uses molecular markers to study

• the evolutionary processes that occur at the level of populations and species boundaries, such as speciation and hybridisation

• the process of molecular evolution.

The molecular data used in these programs are analysed phylogenetically requiring the continuous development of:

• new molecular markers, especially in those groups where published nucleotide sequence data are scarce and where there a fewer active researchers.

• models of molecular evolution that are increasingly realistic.

• computer based procedures for tree-building and phylogeny testing.

Studies of the processes that occur within and between closely related populations provide our understanding of the mechanism of evolution. Understanding the behaviour of genes in these circumstances allows for the interpretation of molecular systematic data.

Understanding the structure, arrangement and diversity of genetic material at the molecular level is also important for the interpretation of the data generated in molecular systematic laboratories.

2) Molecular Markers for Natural Resource Management

This program provides molecular markers for identification of individuals at the species level and below.

There are a large variety of applied uses for individual identifications that can be achieved with molecular genetic markers, ranging from basic biodiversity cataloguing to the identification of biomedically important organisms and "forensic" identifications.

Examples of Current Research Programs - Evolutionary Biology Unit

Evolutionary Relationships of the Australasian Python radiation

Pythons are non-venomous snakes that have their greatest diversity in the Australian region. Most of the species (17) are found in Australia and New Guinea but one genus, Python, is found from Indonesia through to Africa. Some of the spectacularly patterned species are becoming increasingly popular as pets while others are of conservation concern. Some species such as the carpet python are common, widespread and very variable and may constitute more than one species. In order to better understand the evolutionary relationships between all groups of pythons and to establish the number of species and distinct populations, we are using molecular techniques to study mitochondrial and nuclear DNA sequence variation. This information can also be used for the conservation and management of genetically distinct populations. We will also examine some controversial ideas on the relationships between Python and the genera from the Australian region.

Participants:

• Lesley Rawlings, PhD student University of Adelaide
  

• Phil Jordan, B.Sc Honours student, Biological Sciences, Flinders University

• Prof Amanda Goodman, Biological Sciences, Flinders University

Research Manager : Steve Donnellan, donnellan.steve@saugov.sa.gov.au

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Evolutionary relationships and the genetics of social structure in some Australian lizards.

Although much is known about the social systems of birds, mammals and insects, research into the sociality of lizards is scarce. This project will study the sociality in Australian lizards at two different levels. Firstly, the evolutionary relationships among skink lizards of the Egernia group will be established with nuclear and mitochondrial gene markers. The Egernia group includes the more commonly known Australian lizards such as the gidgee skink, blue-tongue lizard and the sleepy or stumpy tail lizard. The interesting aspect about this group of lizards is that different species within the Egernia group exhibit different social structures from solitary to communally living species. A phylogeny will be used to determine whether all the group living species have a common ancestor or have independently evolved this social behaviour. The second part of this project will then zoom in on the gidgee skink, a species of Egernia group that lives in rock crevices in supposed family groups. DNA microsatellite markers will be used to investigate the genetic relatedness and relationships within and between these crevice living groups. This study will result in a greater understanding of the sociality of lizards. The work is funded by the Australian Research Council and a South Australian Museum postgraduate award.

Participant: Mike Gardner : Scientist, South Australian Museum
gardner.michael@saugov.sa.gov.au

Research Manager : Steve Cooper, cooper.steven@saugov.sa.gov.au

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Evolution of sociality and mating strategies in Carpenter bees (Xylocopa): A combined phylogenetic and behavioural approach.

Evolution of social behaviour and organisation has reached an extreme in some insect groups such as ants and bees, such that some individuals are morphologically adapted for a limited number of roles in the colony and forgo the opportunity to reproduce. The evolutionary pathways to the development to this extreme are not well established.

This project examines the early steps in the evolution of sociality, using a group of bees which straddle the threshold between solitary and social behaviour. The aim is to estimate the phylogeny of the genus Xylocopa at the subgeneric level using DNA sequence data from two nuclear and two mitochondrial genes. The genus has a world-wide distribution. The phylogeny will be used to study the evolution of sociality and mating strategies in this group. The pattern of speciation of the Australian species of the subgenus Koptortosoma will be studied in greater detail. The project is funded by the Australian Research Council for 1996-1999.

Participant: Remko Leijs PhD student Flinders University and South Australian Museum. remko.leijs@flinders.edu.au
Research Manager : Steve Cooper, cooper.steven@saugov.sa.gov.au

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The evolution of placentation among Australian scincid lizards

The mode of reproduction among species of reptiles includes oviparity (egg-laying), viviparity (live-born young) with placental nutrient provision, and an intermediate pattern in which both yolk and placental nourishment are provided to embryos. Viviparity has evolved on numerous occasions in the history of squamate reptiles (lizards and snakes), and all of these patterns are represented among the Australian species of the lizard family Scincidae. This project aims to establish with confidence the evolutionary relationships of the viviparous Australian and New Zealand members of the Eugongylus group, which we will base on a combination of DNA sequence data and morphology. At the same time we will describe extraembryonic membrane and uterine development in relationship to the pattern of embryonic nutrition among oviparous and viviparous species. The phylogenetic hypothesis will then be used to map the structural and functional evolution of placental viviparity in these lizards. The project is funded by the Australian Research Council for 1998-2000 and is being conducted in collaboration with Dr Jim Stewart, Department of Biological Sciences, East Tennessee State University, Johnson City, TN 37614 USA. Email stewarjr@Access.etsu.edu

Participant: Sarah Smith PhD student University of Adelaide and South Australian Museum smith.sarah@saugov.sa.gov.au
Research Manager : Steve Donnellan, donnellan.steve@saugov.sa.gov.au

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Conservation Genetics - Molecular Markers for identifying management units and managing genetic diversity

This project examines the species level systematics and management unit structure of species that are a concern for conservation by using molecular genetic methods to describe the geographic and historical distribution of genetic diversity. Some current subjects of investigation are:

• Eastern Australian wet forest frogs of the genus Litoria with Mick Mahony (email: bimjm@cc.newcastle.edu.au) and Ross Knowles (email: rossknowles@bigpond.com), Newcastle University.

• The Southern Emu Wren (Stipiturus malachurus), with the Conservation Council of South Australia

• The threatened Malleefowl (Leipoa ocellata), with the South Australian Department of Environment, Heritage, and Aboriginal Affairs.

• The Echidna (Tachyglossus aculeatus).

• The Kowari (Dasyuroides) and Mulgara (Dasycercus), with the South Australian Department of Environment, Heritage, and Aboriginal Affairs.

• Small native rodents (Pseudomys), with Conservation and Land Management - Western Australia, National Parks - Northern Territory and the South Australian Department of Environment, Heritage, and Aboriginal Affairs.

These projects are funded from a wide variety of government and non-government sources

Research Managers : Steve Donnellan, Senior Research Scientist, donnellan.steve@saugov.sa.gov.au and Mark Adams, Senior Research Scientist, adams.mark@saugov.sa.gov.au

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