Evolution in microsatellite DNA: testing models of mutation in an Australian marsupial. We aim to compare mutational events between microsatellite loci that vary in their exposure to recombination. We are able to do this because of a remarkable finding that Australian brushtail possums have multiple occurrences of a single microsatellite repeat element within the Y-chromosome and among autosomal loci. We will compare variation between the Y-linked and non Y-linked loci within and among individu ....Evolution in microsatellite DNA: testing models of mutation in an Australian marsupial. We aim to compare mutational events between microsatellite loci that vary in their exposure to recombination. We are able to do this because of a remarkable finding that Australian brushtail possums have multiple occurrences of a single microsatellite repeat element within the Y-chromosome and among autosomal loci. We will compare variation between the Y-linked and non Y-linked loci within and among individual possums and use those comparisons to distinguish between recombinant and non- recombinant mutational mechanisms. These data will provide new insights into the mutational mechanisms that drive variation in these most important molecular markers.Read moreRead less
Sex in Dragons: Evolution of sex determination in reptiles. Australia is a leader in sex determination research with major advances in our understanding attributable to Australian researchers and laboratories. This project will contribute to our prestige as a nation capable of contributing cutting edge research directions and stimulating ideas in human sex determination. Moreover, many reptiles have temperature-dependent sex determination, and so would appear appallingly vulnerable to climate ch ....Sex in Dragons: Evolution of sex determination in reptiles. Australia is a leader in sex determination research with major advances in our understanding attributable to Australian researchers and laboratories. This project will contribute to our prestige as a nation capable of contributing cutting edge research directions and stimulating ideas in human sex determination. Moreover, many reptiles have temperature-dependent sex determination, and so would appear appallingly vulnerable to climate change. Our project, will bring improved understanding of sex determination in reptiles, identify evolutionary responses of reptiles to climate change, and assist by informing society on how we might manage this issue into the future conservation of these unique Australian reptiles. Read moreRead less
Sex in Dragons: The molecular basis of genetic and environmental sex determination. How animals determine sex has been debated over decades. Particularly mysterious is that sex is determined by genes in some animals, and by temperature in others. We will study closely related dragon lizards which determine sex via genes (GSD) or temperature (TSD). We will use novel genetic, molecular and cytological aproaches to discover genes and chromosomes that control sex determination in the GSD species, an ....Sex in Dragons: The molecular basis of genetic and environmental sex determination. How animals determine sex has been debated over decades. Particularly mysterious is that sex is determined by genes in some animals, and by temperature in others. We will study closely related dragon lizards which determine sex via genes (GSD) or temperature (TSD). We will use novel genetic, molecular and cytological aproaches to discover genes and chromosomes that control sex determination in the GSD species, and explore their homologues in the TSD species. We expect this study will provide new insights to mechanisms of sex determination in all vertebrates, and demonstrate how genes and the environment interact to control the process.Read moreRead less
Organization, function and evolution of marsupial Y chromosomes. The Y chromosome of humans and other mammals contains only a few genes, most specialized for male sex and reproduction. How the Y chromosome evolved to be so peculiar has been debated for 90 years. It began as an ordinary chromosome, but has degraded until there is almost nothing left, and it is likely to disappear in about 13 million years. Molecular characterization of the Y chromosomes of distantly related mammals could serve to ....Organization, function and evolution of marsupial Y chromosomes. The Y chromosome of humans and other mammals contains only a few genes, most specialized for male sex and reproduction. How the Y chromosome evolved to be so peculiar has been debated for 90 years. It began as an ordinary chromosome, but has degraded until there is almost nothing left, and it is likely to disappear in about 13 million years. Molecular characterization of the Y chromosomes of distantly related mammals could serve to 're-run the evolutionary tape', but the Y chromosome has been left out of whole genome sequencing because it is hard to do efficiently. We developed a novel technique to isolate DNA sequences and genes on the Y chromosome in three species of marsupials, which are especially valuable because they are so different from human and mouse.Read moreRead less
Sex in Dragons: Probing the genotype-phenotype interaction in sex determination. Reptiles have two modes of sex determination: genetic (GSD) and temperature dependent (TSD). We will determine if there is an underlying mechanism of sex determination common to TSD and GSD reptiles by comparing the genomes of two sister species of dragon lizard that differ in their mode of sex determination. This study will provide new insights to the mechanism of sex determination in vertebrates and will test the ....Sex in Dragons: Probing the genotype-phenotype interaction in sex determination. Reptiles have two modes of sex determination: genetic (GSD) and temperature dependent (TSD). We will determine if there is an underlying mechanism of sex determination common to TSD and GSD reptiles by comparing the genomes of two sister species of dragon lizard that differ in their mode of sex determination. This study will provide new insights to the mechanism of sex determination in vertebrates and will test the proposition that sex determination results from the interaction between environmental influences and an underlying genetic component.Read moreRead less
Solving the Mysteries of Monotreme Chromosomes. The peculiar chromosomes of Australia's platypus and echidna have been debated for more than 30 years. Classical cytology cannot resolve the puzzling sex chromosome system, or to sort out the bizarre translocation chain (unique in vertebrates) and deduce how it segregates to make viable zyotes. I will microdissect individual chromosomes, and use DNA ?paints? from them (and gene probes isolated by them) to detect homologies between unpaired chromoso ....Solving the Mysteries of Monotreme Chromosomes. The peculiar chromosomes of Australia's platypus and echidna have been debated for more than 30 years. Classical cytology cannot resolve the puzzling sex chromosome system, or to sort out the bizarre translocation chain (unique in vertebrates) and deduce how it segregates to make viable zyotes. I will microdissect individual chromosomes, and use DNA ?paints? from them (and gene probes isolated by them) to detect homologies between unpaired chromosomes at mitosis, meiosis and in sperm. I will use immunohistochemistry to clarify chromosome pairing and recombination at meiosis. This will answer some important general questions about chromosome behaviour and sex chromosome evolution.
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Genetic control of floral architecture. Different flowers have different designs, and so the design must ultimately be controlled by genes. We have identified a gene that keeps sepals separate, and promotes the initiation of petals. We think it does this by a novel growth suppression mechanism, and will now deduce its molecular and cellular basis. This will help maintain Australia's strength in fundamental plant biology. Also, by understanding how sepals and petals arise in a model laboratory sp ....Genetic control of floral architecture. Different flowers have different designs, and so the design must ultimately be controlled by genes. We have identified a gene that keeps sepals separate, and promotes the initiation of petals. We think it does this by a novel growth suppression mechanism, and will now deduce its molecular and cellular basis. This will help maintain Australia's strength in fundamental plant biology. Also, by understanding how sepals and petals arise in a model laboratory species, we can generalise for many species, including economic plants. Thus it may be possible to make designer crops through targeted genetic changes to their floral structure.Read moreRead less
Control of plant organ development by the PETAL LOSS gene of Arabidopsis. We have discovered a new gene in the model laboratory plant Arabidopsis thaliana that is involved in sepal and petal development. It encodes a transcription factor that apparently acts by repressing growth in the inter-sepal zone of flowers where petals arise. We now aim to determine how this growth suppression occurs, and whether it extends to leaves where the gene is also expressed. Control of the initiation and sculptur ....Control of plant organ development by the PETAL LOSS gene of Arabidopsis. We have discovered a new gene in the model laboratory plant Arabidopsis thaliana that is involved in sepal and petal development. It encodes a transcription factor that apparently acts by repressing growth in the inter-sepal zone of flowers where petals arise. We now aim to determine how this growth suppression occurs, and whether it extends to leaves where the gene is also expressed. Control of the initiation and sculpturing of plant organs by site-specific inhibition of growth is a newly discovered mechanism that may be useful in manipulating plant architecture.Read moreRead less
Understanding how auxin and dorsoventral patterning are coordinated in plants. This study will help reveal for the first time how the outgrowth of leaves, flowers and floral organs is coordinated by tissue patterning genes and the plant growth hormone auxin. All plants grow in this way, and our findings, made using a model laboratory plant, will be applicable to crop species as well. Thus we will both expand our core knowledge of how multicellular organisms are constructed, and also generate pos ....Understanding how auxin and dorsoventral patterning are coordinated in plants. This study will help reveal for the first time how the outgrowth of leaves, flowers and floral organs is coordinated by tissue patterning genes and the plant growth hormone auxin. All plants grow in this way, and our findings, made using a model laboratory plant, will be applicable to crop species as well. Thus we will both expand our core knowledge of how multicellular organisms are constructed, and also generate possibilities for modifying the patterns of leaf and flower development in agricultural and horticultural species. Crops with larger leaves, or flowers of different structure, may result.Read moreRead less
Adaptive Evolution of BRCA1 in Ancestral Mammals. This project investigates adaptive evolution of BRCA1 in the early radiation of mammals. We will test the hypothesis that the evolution of mammary glands and X chromosome inactivation has resulted in modification of the BRCA1 protein sequence as it aquired new roles in these processes. We will also investigate the importance of these changes inducing compensatory changes in other parts of the protein.