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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Role Of The Anaphase-Promoting Complex Activator Cdh1 In Oocyte Maturation And Meiotic Aneuploidy
Funder
National Health and Medical Research Council
Funding Amount
$526,878.00
Summary
Eggs containing an incorrect number of chromosomes are described as aneuploid. This project sets out to examine the molecular causes of aneuploidy and why it increases with female age. We focus on the protective role of the protein Cdh1 in this process. The outcome would be to better understand the origins of aneuploidy so as to find methods of decreasing it as women age. This is highly significant given aneuploidy is the leading cause of early embryo loss and produces Down Syndrome babies.
Chromosomes are structures that carry genes in all our cells. Every human cell has 46 chromosomes. In the nucleus of eukaryotic cells, DNA is highly folded and compacted with specific proteins into a dynamic polymer called chromatin. Gene expression, chromosome division, DNA replication, and repair all act, not on DNA alone, but on this chromatin template. The discovery that enzymes can (re)organise chromatin into accessible and inaccessible configurations revealed mechanisms that considerably e ....Chromosomes are structures that carry genes in all our cells. Every human cell has 46 chromosomes. In the nucleus of eukaryotic cells, DNA is highly folded and compacted with specific proteins into a dynamic polymer called chromatin. Gene expression, chromosome division, DNA replication, and repair all act, not on DNA alone, but on this chromatin template. The discovery that enzymes can (re)organise chromatin into accessible and inaccessible configurations revealed mechanisms that considerably extend the information potential of the genetic code. In addition, it is now established that chromatin structural features can influence gene expression. In vitro studies support a model in which chromatin functions as a barrier for the access to DNA. Therefore this organization has to be tighly regulated and dynamic to allow the protein-DNA interactions critical for nuclear functions. Importantly genome organisation provides in addition to genetic information another layer of information, so called epigenetic, which by definition means that it is stably inherited throughout cellular divisions, yet it is not encoded genetically. Thus each cell type will display a specific epigenome. We have recently constructed small human minichromosomes, which are much easier to study than the much larger normal chromosomes. The present project proposes to define the epigenetic feature across an entire human chromosome using our minichhromosomes as working models. The outcome will be a significant gain in our knowledge on the processes underlying epigenetic regulation, the organisation of specialised chromatin domain, and behaviour of the chromosomes.Read moreRead less
The Cytochrome P450 Gene Super-family in Drosophila melanogaster; Gene Function and Insecticide Resistance. The cytochrome P450 (Cyp) gene super-family is represented by over 90 sequences in the genome of the vinegar fly, Drosophila melanogaster. To date, four Cyp genes are found to be involved in insecticide resistance. The function of the majority of Cyp genes is unknown. This project will investigate the function and regulation of D. melanogaster Cyp genes, linking the fly's genotype to its ....The Cytochrome P450 Gene Super-family in Drosophila melanogaster; Gene Function and Insecticide Resistance. The cytochrome P450 (Cyp) gene super-family is represented by over 90 sequences in the genome of the vinegar fly, Drosophila melanogaster. To date, four Cyp genes are found to be involved in insecticide resistance. The function of the majority of Cyp genes is unknown. This project will investigate the function and regulation of D. melanogaster Cyp genes, linking the fly's genotype to its phenotype. By studying the effects of Cyp genes on fly survival, Cyp gene expression and regulation, and expressing selected Cyp genes in a yeast expression system, we will enhance our understanding of Cyp gene function and evolution.Read moreRead less
Many Ys in monotremes: multiple sex chromosomes and sex determination in platypus and echidna. Platypus and Echidna are Australian icons, even featuring on our coins. Their unusual biology and ancient relationship to humans make them unique for understanding the mammalian genome, as demonstrated by our recent discovery of ten sex chromosomes in platypus that link mammal and bird sex. Still little is known about their genome, embryo development and how sex is determined. We will identify new gene ....Many Ys in monotremes: multiple sex chromosomes and sex determination in platypus and echidna. Platypus and Echidna are Australian icons, even featuring on our coins. Their unusual biology and ancient relationship to humans make them unique for understanding the mammalian genome, as demonstrated by our recent discovery of ten sex chromosomes in platypus that link mammal and bird sex. Still little is known about their genome, embryo development and how sex is determined. We will identify new genes on all ten sex chromosomes and investigate how they determine sex. The set up of an Australian Monotreme Resource Centre will be crucial for this research and attract worldwide high profile collaborations. We will answer important general questions in monotreme biology and contribute to our understanding of sexual abnormalities in humans.Read moreRead less
Isolation and characterization of genes regulating female reproductive organ development in plants. Genes that regulate female reproductive organ development are of immense value for Australia as tools for seed improvement. Those from our preliminary screen have convinced our industry partners that they can be agents for engineering of apomixis or creation of fertile seed without fertilisation. This will allow the capture of hybrid vigour in wheat and rice, for which commercial hybrid seed prod ....Isolation and characterization of genes regulating female reproductive organ development in plants. Genes that regulate female reproductive organ development are of immense value for Australia as tools for seed improvement. Those from our preliminary screen have convinced our industry partners that they can be agents for engineering of apomixis or creation of fertile seed without fertilisation. This will allow the capture of hybrid vigour in wheat and rice, for which commercial hybrid seed production is not currently available. In wheat alone, apomixis presents for Australia an economic value of more than Aus$ ½ billion per annum. Furthermore, controlled apomixis will accelerate breeding programs that will bring drought resistance and minimal fertiliser requiring varieties to the farmer.Read moreRead less
Control of meiosis and embryogenesis as a means to induce higher plants to reproduce asexually through seed. New plant meiosis-control genes will be isolated and characterised. These will be used, together with cell proliferation control genes characterised in the applicant's laboratory, to control gamete formation and embryo development in higher plants, and hence plant reproduction. This research will provide a platform for genetic fixation of hybrid vigour and repeat propagation of F1 hybrid ....Control of meiosis and embryogenesis as a means to induce higher plants to reproduce asexually through seed. New plant meiosis-control genes will be isolated and characterised. These will be used, together with cell proliferation control genes characterised in the applicant's laboratory, to control gamete formation and embryo development in higher plants, and hence plant reproduction. This research will provide a platform for genetic fixation of hybrid vigour and repeat propagation of F1 hybrid seed without attenuation of vigour. The technology will increase yield and profitability for Australian agriculture, and ensure access to technology that the industry partner will otherwise develop overseas. The technology benefits most major crops that are bred and grown to meet increasing demand for food and speciality products for pharmaceutical or industrial purposes.Read moreRead less