Small is beautiful: Did gene-rich regions of mammal chromosomes evolve from microchromosomes? Most birds and reptile genomes feature many tiny microchromosomes. These are not junk, as previously thought, but contain most of the genes. Mammals lack microchromosomes, but contain gene-rich regions with similar attributes. We suggest that microchromosomes originated by genome duplication, and evolved into the gene-rich regions of mammalian chromosomes. We will test this hypothesis by comparing seque ....Small is beautiful: Did gene-rich regions of mammal chromosomes evolve from microchromosomes? Most birds and reptile genomes feature many tiny microchromosomes. These are not junk, as previously thought, but contain most of the genes. Mammals lack microchromosomes, but contain gene-rich regions with similar attributes. We suggest that microchromosomes originated by genome duplication, and evolved into the gene-rich regions of mammalian chromosomes. We will test this hypothesis by comparing sequences and genes in microchromosomes of birds, reptiles and monotremes. This will clarify the origin and evolution of the ?microgenome?, establish its suitability as a model for vertebrate genome organisation, and demonstrate whether microchromosomes are the ancestors of the gene-rich regions of mammalian chromosomes.Read moreRead less
Endosymbiotic DNA transfer. Interorganellar DNA movement is a major force in evolution. In higher organisms, the prokaryotic ancestors of mitochondria and chloroplasts donated many genes to the nucleus. Plants have unique potential in studies of the mechanisms that have driven genome evolution. We established experimentally that DNA moves from the chloroplast to the nucleus at high frequency and this provided us with a world lead in this scientifically new area. The relocated genes contribute to ....Endosymbiotic DNA transfer. Interorganellar DNA movement is a major force in evolution. In higher organisms, the prokaryotic ancestors of mitochondria and chloroplasts donated many genes to the nucleus. Plants have unique potential in studies of the mechanisms that have driven genome evolution. We established experimentally that DNA moves from the chloroplast to the nucleus at high frequency and this provided us with a world lead in this scientifically new area. The relocated genes contribute to the number and diversity of genes and gene function. Genetically manipulated (GM) crops use the chloroplast compartment to make high levels of protein, necessitating a full understanding of how transgenes behave within the cellular and the external environment.Read moreRead less
Trafficking of DNA between chloroplast and nucleus in higher plants. Reliably high levels of diverse proteins can be produced in plant chloroplasts. Environmental risks are considered low for chloroplast genes because they are not transmitted by pollen. However, we recently discovered that DNA escapes from the tobacco chloroplast to the nucleus with unexpectedly high frequency. The associated environmental risks require immediate investigation. This project will determine the fate of chloroplast ....Trafficking of DNA between chloroplast and nucleus in higher plants. Reliably high levels of diverse proteins can be produced in plant chloroplasts. Environmental risks are considered low for chloroplast genes because they are not transmitted by pollen. However, we recently discovered that DNA escapes from the tobacco chloroplast to the nucleus with unexpectedly high frequency. The associated environmental risks require immediate investigation. This project will determine the fate of chloroplast DNA that has moved to the nuclear genome and gain insight into the evolutionary and environmental consequences of chloroplast DNA escape. The ubiquity of DNA escape also will be studied in an edible crop with a small genome, tomato.Read moreRead less
Analysis of interorganellar transposition of DNA. The movement of DNA between organelles is a major driving force in the eukaryotic evolution. In yeast about 75% of all nuclear genes may derive from protomitochondria. Though DNA transfer per se continues in all higher cells, including mammals, in most species the functional transfer of genes has stopped. It continues at a high rate in plants, giving them unique potential in evolutionary studies of the genome. We established experimentally that D ....Analysis of interorganellar transposition of DNA. The movement of DNA between organelles is a major driving force in the eukaryotic evolution. In yeast about 75% of all nuclear genes may derive from protomitochondria. Though DNA transfer per se continues in all higher cells, including mammals, in most species the functional transfer of genes has stopped. It continues at a high rate in plants, giving them unique potential in evolutionary studies of the genome. We established experimentally that DNA moves frequently from the plastid (chloroplast) to the nucleus. We now aim to measure the frequency of DNA transposition from the plastid to the mitochondrion. If transposition is sufficiently frequent, the approach can be used to transformation the mitochondrial genome.Read moreRead less
The molecular basis of endosymbiotic evolution. First: Timmis has a 20 year, pioneering reputation in this research area which has recently emerged as a major focus in evolutionary genetics, genomics and GM crop technology. Four years of recent ARC funding has enabled us to remain internationally competitive and significant papers and collaborative reviews in high-impact journals have resulted, to the benefit of Australia's reputation in biolological science. Second: our recent results have caus ....The molecular basis of endosymbiotic evolution. First: Timmis has a 20 year, pioneering reputation in this research area which has recently emerged as a major focus in evolutionary genetics, genomics and GM crop technology. Four years of recent ARC funding has enabled us to remain internationally competitive and significant papers and collaborative reviews in high-impact journals have resulted, to the benefit of Australia's reputation in biolological science. Second: our recent results have caused major debate about containment of GM crops. The knowledge gained from this research will provide essential information to ensure against environmental and human problems associated with transgene escape from GM crops into wild species.Read moreRead less
The genetic and molecular organisation of the self incompatibility gene region in the grasses. Self-incompatibility (SI) is a cell-cell recognition process used by plants to prevent self-pollination and force outcrossing. It is widespread, occurring in a third of plant families. Although studies of SI go back to the 1800s, the origin of SI remains a mystery. Recent advances in the molecular characterisation of SI loci in some species has re-ignited debate on its origins but has provided few answ ....The genetic and molecular organisation of the self incompatibility gene region in the grasses. Self-incompatibility (SI) is a cell-cell recognition process used by plants to prevent self-pollination and force outcrossing. It is widespread, occurring in a third of plant families. Although studies of SI go back to the 1800s, the origin of SI remains a mystery. Recent advances in the molecular characterisation of SI loci in some species has re-ignited debate on its origins but has provided few answers. This project uses the grasses to explore the origins of SI. As a model system, the grasses offer detailed genetic and molecular data and aspects of floral architecture associated with SI can be investigatedRead moreRead less