16 research outputs found

    A Massively Parallel Sequencing Approach Uncovers Ancient Origins and High Genetic Variability of Endangered Przewalski's Horses

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    The endangered Przewalski's horse is the closest relative of the domestic horse and is the only true wild horse species surviving today. The question of whether Przewalski's horse is the direct progenitor of domestic horse has been hotly debated. Studies of DNA diversity within Przewalski's horses have been sparse but are urgently needed to ensure their successful reintroduction to the wild. In an attempt to resolve the controversy surrounding the phylogenetic position and genetic diversity of Przewalski's horses, we used massively parallel sequencing technology to decipher the complete mitochondrial and partial nuclear genomes for all four surviving maternal lineages of Przewalski's horses. Unlike single-nucleotide polymorphism (SNP) typing usually affected by ascertainment bias, the present method is expected to be largely unbiased. Three mitochondrial haplotypes were discovered—two similar ones, haplotypes I/II, and one substantially divergent from the other two, haplotype III. Haplotypes I/II versus III did not cluster together on a phylogenetic tree, rejecting the monophyly of Przewalski's horse maternal lineages, and were estimated to split 0.117–0.186 Ma, significantly preceding horse domestication. In the phylogeny based on autosomal sequences, Przewalski's horses formed a monophyletic clade, separate from the Thoroughbred domestic horse lineage. Our results suggest that Przewalski's horses have ancient origins and are not the direct progenitors of domestic horses. The analysis of the vast amount of sequence data presented here suggests that Przewalski's and domestic horse lineages diverged at least 0.117 Ma but since then have retained ancestral genetic polymorphism and/or experienced gene flow

    Bone histology provides insights into the life history mechanisms underlying dwarfing in hipparionins

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    Size shifts may be a by-product of alterations in life history traits driven by natural selection. Although this approach has been proposed for islands, it has not yet been explored in continental faunas. The trends towards size decrease experienced by some hipparionins constitute a good case study for the application of a life history framework to understand the size shifts on the continent. Here, we analysed bone microstructure to reconstruct the growth of some different-sized hipparionins from Greece and Spain. The two dwarfed lineages studied show different growth strategies. The Greek hipparions ceased growth early at a small size thus advancing maturity, whilst the slower-growing Spanish hipparion matured later at a small size. Based on predictive life history models, we suggest that high adult mortality was the likely selective force behind early maturity and associated size decrease in the Greek lineage. Conversely, we infer that resource limitation accompanied by high juvenile mortality triggered decrease in growth rate and a relative late maturity in the Spanish lineage. Our results provide evidence that different selective pressures can precipitate different changes in life history that lead to similar size shifts

    Finland framstäldt i teckningar. : Texten af Z. Topelius. Plancherna från Adler & Dietz i Dresden.

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    Lithographs from: Johan Knutson, Magnus v. Wright, Lennart Forstén, Pehr Adolf Kruskopf, F. J. Westerling, Adolf Wilhelm Lindeström, and J. Boström, and two lithographs without the artistʼs name.Digital reproduction, The National Library of Finland, Centre for Preservation and Digitisation, MikkeliZacharias Topelius, a prominent writer and journalist, and a professor of history, consciously created the cultural image of Finland with his writings. The book (Finland represented in illustrations) has illustrated works which included pictures by the most famous Finnish 19th century artists. The aim of the book was to create a panorama of the history of Finland, and of its memorable places and scenic regions. The selection of illustrations included in this work were based on Topeliusʼs own selection programme and criteria.TravelEuropeanaTopelius, Zacharias (1818-1898)Knutson, Johan (1816-1899)Wright, Magnus von (1805-1868)Forstén, Lennart (1817-1886)Kruskopf, P. A. (1805-1852

    100 GHz zinc oxide Schottky diodes processed from solution on a wafer scale

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    Inexpensive radio-frequency devices that can meet the ultrahigh-frequency needs of fifth- and sixth-generation wireless telecommunication networks are required. However, combining high performance with cost-effective scalable manufacturing has proved challenging. Here, we report the fabrication of solution-processed zinc oxide Schottky diodes that can operate in microwave and millimetre-wave frequency bands. The fully coplanar diodes are prepared using wafer-scale adhesion lithography to pattern two asymmetric metal electrodes separated by a gap of around 15 nm, and are completed with the deposition of a zinc oxide or aluminium-doped ZnO layer from solution. The Schottky diodes exhibit a maximum intrinsic cutoff frequency in excess of 100 GHz, and when integrated with other passive components yield radio-frequency energy-harvesting circuits that are capable of delivering output voltages of 600 mV and 260 mV at 2.45 GHz and 10 GHz, respectively.</p

    Pliocene‐Pleistocene Stratigraphy and Sea‐Level Estimates, Republic of South Africa With Implications for a 400 ppmv CO 2

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    The Mid-Pliocene Warm Period (MPWP, 2.9 to 3.3 Ma), along with older Pliocene (3.2 to 5.3 Ma) records, offers potential past analogues for our 400-ppmv world. The coastal geology of western and southern coasts of the Republic of South Africa exposes an abundance of marine deposits of Pliocene and Pleistocene age. In this study, we report differential GPS elevations, detailed stratigraphic descriptions, standardized interpretations, and dating of relative sea-level indicators measured across ~700 km from the western and southern coasts of the Cape Provinces. Wave abrasion surfaces on bedrock, intertidal sedimentary structures, and in situ marine invertebrates including oysters and barnacles provide precise indicators of past sea levels. Multiple sea-level highstands imprinted at different elevations along South African coastlines were identified. Zone I sites average +32 ± 5 m (six sites). A lower topographic Zone II of sea stands were measured at several sites around +17 ± 5 m. Middle and late Pleistocene sites are included in Zone III. Shoreline chronologies using 87Sr/86Sr ages on shells from these zones yield ages from Zone I at 4.6 and 3.0 Ma and Zone II at 1.04 Ma. Our results show that polar ice sheets during the Plio-Pleistocene were dynamic and subject to significant melting under modestly warmer global temperatures. These processes occurred during a period when CO2 concentrations were comparable to our current and rapidly rising values above 400 ppmv

    Equus kiang (Perissodactyla: Equidae)

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    Equus kiang Moorcroft, 1841, is an equid commonly called the kiang or Tibetan wild ass and is the only equid living on the Tibetan Plateau. It is the largest of the wild asses, with a distinct dark-brown coat on the back, and 1 of the 7 species of Equus. It is endemic to the high-elevation rangelands of China (Tibet, Xinjiang, Qinghai, and Gansu), India (Ladakh and Sikkim), Pakistan (Khunjerab National Park), and Nepal (Mustang). It inhabits open steppes and rolling hills sparsely vegetated with grasses and sedges. E. kiang is vulnerable to illegal poaching and competition with domestic livestock, and data are insufficient to accurately estimate its total abundance
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