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Dinoflagellates are algae of tremendous importance to ecosystems and to public health. The cell biology and genome organization of dinoflagellate species is highly unusual. For example, the plastid genomes of peridinin-containing dinoflagellates encode only a minimal number of genes arranged on small elements termed "minicircles". Previous studies of peridinin plastid genes have found evidence for divergent sequence evolution, including extensive substitutions, novel insertions and deletions, and use of alternative translation initiation codons. Understanding the extent of this divergent evolution has been hampered by the lack of characterized peridinin plastid sequences. We have identified over 300 previously unannotated peridinin plastid mRNAs from published transcriptome projects, vastly increasing the number of sequences available. Using these data, we have produced a well-resolved phylogeny of peridinin plastid lineages, which uncovers several novel relationships within the dinoflagellates. This enables us to define changes to plastid sequences that occurred early in dinoflagellate evolution, and that have contributed to the subsequent diversification of individual dinoflagellate clades. We find that the origin of the peridinin dinoflagellates was specifically accompanied by elevations both in the overall number of substitutions that occurred on plastid sequences, and in the Ka/Ks ratio associated with plastid sequences, consistent with changes in selective pressure. These substitutions, alongside other changes, have accumulated progressively in individual peridinin plastid lineages. Throughout our entire dataset, we identify a persistent bias toward non-synonymous substitutions occurring on sequences encoding photosystem I subunits and stromal regions of peridinin plastid proteins, which may have underpinned the evolution of this unusual organelle.

Dinoflagellates are a group of unicellular protists with immense ecological and evolutionary significance and cell biological diversity. Of the photosynthetic dinoflagellates, the majority possess a plastid containing the pigment peridinin, whereas some lineages have replaced this plastid by serial endosymbiosis with plastids of distinct evolutionary affiliations, including a fucoxanthin pigment-containing plastid of haptophyte origin. Previous studies have described the presence of widespread substitutional RNA editing in peridinin and fucoxanthin plastid genes. Because reports of this process have been limited to manual assessment of individual lineages, global trends concerning this RNA editing and its effect on the biological function of the plastid are largely unknown. Using novel bioinformatic methods, we examine the dynamics and evolution of RNA editing over a large multispecies data set of dinoflagellates, including novel sequence data from the peridinin dinoflagellate Pyrocystis lunula and the fucoxanthin dinoflagellate Karenia mikimotoi. We demonstrate that while most individual RNA editing events in dinoflagellate plastids are restricted to single species, global patterns, and functional consequences of editing are broadly conserved. We find that editing is biased toward specific codon positions and regions of genes, and generally corrects otherwise deleterious changes in the genome prior to translation, though this effect is more prevalent in peridinin than fucoxanthin lineages. Our results support a model for promiscuous editing application subsequently shaped by purifying selection, and suggest the presence of an underlying editing mechanism transferred from the peridinin-containing ancestor into fucoxanthin plastids postendosymbiosis, with remarkably conserved functional consequences in the new lineage.

University of Technology, Sydney. Faculty of Education. NO FULL TEXT AVAILABLE. Access is restricted indefinitely. The hardcopy may be available for consultation at the UTS Library. NO FULL TEXT AVAILABLE. Access is restricted indefinitely. ----- The aim of this thesis is to determine why technical education was so generously supported by a number of philanthropists in Victoria during the period 1860-1940 and to only a lesser extent in the other Australian states. The thesis looks initially at Australia overall before focusing upon Victoria, the field of philanthropy in general during this period is explored, the development of both general and technical education is outlined and the lives of the philanthropists involved are investigated. These aspects are set within the political, economic, social and cultural milieu of the period 1860-1940. It is largely an historical hermeneutic study; reviewing the literature in these three major areas and discussing the issues that surfaced. In relation to specific topics, quantitative surveys were also undertaken to determine the extent and value of philanthropic benefactions, the establishment of educational institutions particularly technical colleges and the lives and backgrounds of the philanthropists. The thesis endeavours to describe, analyse, identify, interpret and discuss the contributions made by major benefactors to vocational education in Victoria in the period between 1860 and 1940 within this overall framework. The thesis focuses on philanthropy as a particular phenomena and its links with society and technical and vocational education of this era in Victoria, drawing parallels with other colonies and states. It addresses the research questions from a point of view of how to understand and explain philanthropy in vocational and technical education. The primary purpose of the thesis is 'understanding' so there is a need to look critically at historical interpretations of philanthropy to see how they can provide a better understanding of social and cultural values and endeavours to relate social policy directly to the philanthropy of a given era. 1bis thesis is not just a journey into the past; it is an examination as to why, within a specific period, some persons found it incumbent upon themselves to organise and financially support technical education in Victoria. It pays belated tribute to these philanthropists who gave so much to technical education but whose contribution has never really been adequately acknowledged and the memory of whom has almost gone. It also attempts to record the 'unhonoured army' whose combined efforts in lesser ways were of tremendous importance to the development of technical education.