29 research outputs found

    Phylogenomics of Rhodobacteraceae reveals evolutionary adaptation to marine and non-marine habitats.

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    Marine Rhodobacteraceae (Alphaproteobacteria) are key players of biogeochemical cycling, comprise up to 30% of bacterial communities in pelagic environments and are often mutualists of eukaryotes. As 'Roseobacter clade', these 'roseobacters' are assumed to be monophyletic, but non-marine Rhodobacteraceae have not yet been included in phylogenomic analyses. Therefore, we analysed 106 genome sequences, particularly emphasizing gene sampling and its effect on phylogenetic stability, and investigated relationships between marine versus non-marine habitat, evolutionary origin and genomic adaptations. Our analyses, providing no unequivocal evidence for the monophyly of roseobacters, indicate several shifts between marine and non-marine habitats that occurred independently and were accompanied by characteristic changes in genomic content of orthologs, enzymes and metabolic pathways. Non-marine Rhodobacteraceae gained high-affinity transporters to cope with much lower sulphate concentrations and lost genes related to the reduced sodium chloride and organohalogen concentrations in their habitats. Marine Rhodobacteraceae gained genes required for fucoidan desulphonation and synthesis of the plant hormone indole 3-acetic acid and the compatible solutes ectoin and carnitin. However, neither plasmid composition, even though typical for the family, nor the degree of oligotrophy shows a systematic difference between marine and non-marine Rhodobacteraceae. We suggest the operational term 'Roseobacter group' for the marine Rhodobacteraceae strains.The ISME Journal advance online publication, 20 January 2017; doi:10.1038/ismej.2016.198

    Genetic sources of population epigenomic variation

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    The field of epigenomics has rapidly progressed from the study of individual reference epigenomes to surveying epigenomic variation in populations. Recent studies in a number of species, from yeast to humans, have begun to dissect the cis- and trans-regulatory genetic mechanisms that shape patterns of population epigenomic variation at the level of single epigenetic marks, as well as at the level of integrated chromatin state maps. We show that this information is paving the way towards a more complete understanding of the heritable basis underlying population epigenomic variation. We also highlight important conceptual challenges when interpreting results from these genetic studies, particularly in plants, in which epigenomic variation can be determined both by genetic and epigenetic inheritance

    Gender Discrimination, Entrepreneurial Talent and Self-Employment

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    The trend of female self-employment in Italy is stable, with a low level of participation which confirms the prediction of economic theory on discrimination. We contend that gender discrimination alters the distribution of entrepreneurial talent between employees and self-employed workers. This gives rise to the prediction that the self-employed women are less likely to survive when self-employed than men because the lesser entrepreneurial talent of women will increase their risk of failure. Applying Markovian analysis to ISTAT’s labor market transition matrices we verify this prediction: Many women try to set up on their own, but they fail to remain self-employed both because their lesser entrepreneurial talent and because they try to become entrepreneurs without any previous experience of work. ‘If you think you’re so discriminated against, why don’t you set up on your own?’ Copyright Springer 2005

    The Respiratory System

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    Darwin and his finches: The evolution of a legend

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    Spezielle Pathologie des Gesichtsfeldes

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