11 research outputs found

    Biological flora of New Zealand 14: <i>Metrosideros excelsa</i>, pōhutukawa, New Zealand Christmas tree

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    <div><p>We review the biology and ecology of <i>Metrosideros excelsa</i> (Myrtaceae), an endemic angiosperm evergreen tree. <i>Metrosideros excelsa</i> belongs to a conspicuous and widely distributed Pacific Basin genus, with centres of diversity in both New Zealand and New Caledonia. <i>Metrosideros excelsa</i> is an iconic tree species that forms a significant component of northern New Zealand's exposed coastal headland and cliff vegetation. Where conditions are more favourable, <i>M. excelsa</i> forms tall coastal forest, ranging from simple young high-density stands to diverse mature forest. Inland, <i>M. excelsa</i> stands are confined to the margins of lakes and rivers on the Central Volcanic Plateau, where some may originate from early Māori plantings. <i>Metrosideros excelsa</i> is reliant on stochastic disturbance events (e.g. landslides, volcanic eruptions) to create open sites necessary for regeneration. Mass flowering (December–January), followed by abundant production of wind-dispersed seed maximises chance colonisation of such sites. Since human settlement in New Zealand, the distribution of <i>M. excelsa</i> forest has declined by c. 90% and the southern limit of the species has retreated north. Natural regeneration on the mainland is limited by the infrequency of large-scale disturbances and increased anthropogenic and herbivore pressures. Consequently, <i>M. excelsa</i> forest has become rare and localised on the mainland; monitoring and active management are fundamental to the species' long-term conservation.</p></div

    Mapping the human genetic architecture of COVID-19

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    The genetic make-up of an individual contributes to the susceptibility and response to viral infection. Although environmental, clinical and social factors have a role in the chance of exposure to SARS-CoV-2 and the severity of COVID-191,2, host genetics may also be important. Identifying host-specific genetic factors may reveal biological mechanisms of therapeutic relevance and clarify causal relationships of modifiable environmental risk factors for SARS-CoV-2 infection and outcomes. We formed a global network of researchers to investigate the role of human genetics in SARS-CoV-2 infection and COVID-19 severity. Here we describe the results of three genome-wide association meta-analyses that consist of up to 49,562 patients with COVID-19 from 46 studies across 19 countries. We report 13 genome-wide significant loci that are associated with SARS-CoV-2 infection or severe manifestations of COVID-19. Several of these loci correspond to previously documented associations to lung or autoimmune and inflammatory diseases3,4,5,6,7. They also represent potentially actionable mechanisms in response to infection. Mendelian randomization analyses support a causal role for smoking and body-mass index for severe COVID-19 although not for type II diabetes. The identification of novel host genetic factors associated with COVID-19 was made possible by the community of human genetics researchers coming together to prioritize the sharing of data, results, resources and analytical frameworks. This working model of international collaboration underscores what is possible for future genetic discoveries in emerging pandemics, or indeed for any complex human disease
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