48 research outputs found

    Macroevolution of hyperdiverse flightless beetles reflects the complex geological history of the Sunda Arc

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    The Sunda Arc forms an almost continuous chain of islands and thus a potential dispersal corridor between mainland Southeast Asia and Melanesia. However, the Sunda Islands have rather different geological histories, which might have had an important impact on actual dispersal routes and community assembly. Here, we reveal the biogeographical history of hyperdiverse and flightless Trigonopterus weevils. Different approaches to ancestral area reconstruction suggest a complex east to west range expansion. Out of New Guinea, Trigonopterus repeatedly reached the Moluccas and Sulawesi transgressing Lydekker′s Line. Sulawesi repeatedly acted as colonization hub for different segments of the Sunda Arc. West Java, East Java and Bali are recognized as distinct biogeographic areas. The timing and diversification of species largely coincides with the geological chronology of island emergence. Colonization was not inhibited by traditional biogeographical boundaries such as Wallace’s Line. Rather, colonization patterns support distance dependent dispersal and island age limiting dispersal

    DNA Barcoding for Community Ecology - How to Tackle a Hyperdiverse, Mostly Undescribed Melanesian Fauna

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    Trigonopterus weevils are widely distributed throughout Melanesia and hyperdiverse in New Guinea. They are a dominant feature in natural forests, with narrow altitudinal zonation. Their use in community ecology has been precluded by the "taxonomic impediment". We sampled >6,500 specimens from seven areas across New Guinea; 1,002 specimens assigned to 270 morphospecies were DNA sequenced. Objective clustering of a refined dataset (excluding nine cryptic species) at 3% threshold revealed 324 genetic clusters (DNA group count relative to number of morphospecies = 20.0% overestimation of species diversity, or 120.0% agreement) and 85.6% taxonomic accuracy (the proportion of DNA groups that "perfectly" agree with morphology-based species hypotheses). Agreement and accuracy were best at an 8% threshold. GMYC analysis revealed 328 entities (21.5% overestimation) with 227 perfect GMYC entities (84.1% taxonomic accuracy). Both methods outperform the parataxonomist (19% underestimation; 31.6% taxonomic accuracy). The number of species found in more than one sampling area was highest in the Eastern Highlands and Huon (Sørensen similarity index 0.07, 4 shared species); ⅓ of all areas had no species overlap. Success rates of DNA barcoding methods were lowest when species showed a pronounced geographical structure. In general, Trigonopterus show high α and β-diversity across New Guinea. DNA barcoding is an excellent tool for biodiversity surveys but success rates might drop when closer localities are included. Hyperdiverse Trigonopterus are a useful taxon for evaluating forest remnants in Melanesia, allowing finer-grained analyses than would be possible with vertebrate taxa commonly used to date. Our protocol should help establish other groups of hyperdiverse fauna as target taxa for community ecology. Sequencing delivers objective data on taxa of incredible diversity but mostly without a solid taxonomic foundation and should help pave the road for the eventual formal naming of new species

    A catalogue of Triticum monococcum genes encoding toxic and immunogenic peptides for celiac disease patients

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    The celiac disease (CD) is an inflammatory condition characterized by injury to the lining of the small-intestine on exposure to the gluten of wheat, barley and rye. The involvement of gluten in the CD syndrome has been studied in detail in bread wheat, where a set of “toxic” and “immunogenic” peptides has been defined. For wheat diploid species, information on CD epitopes is poor. In the present paper, we have adopted a genomic approach in order to understand the potential CD danger represented by storage proteins in diploid wheat and sequenced a sufficiently large number of cDNA clones related to storage protein genes of Triticum monococcum. Four bona fide toxic peptides and 13 immunogenic peptides were found. All the classes of storage proteins were shown to contain harmful sequences. The major conclusion is that einkorn has the full potential to induce the CD syndrome, as already evident for polyploid wheats. In addition, a complete overview of the storage protein gene arsenal in T. monococcum is provided, including a full-length HMW x-type sequence and two partial HMW y-type sequences

    Large-scale molecular phylogeny of Cryptorhynchinae (Coleoptera, Curculionidae) from multiple genes suggests American origin and later Australian radiation

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    The monophyly of the highly diverse weevil subfamily Cryptorhynchinae is tested with a dataset of 203 taxa representing 159 genera of Curculionoidea, 105 of them Cryptorhynchinae s.l. We construct a phylogeny based on an alignment of 5523 bp, consisting of fragments from two mitochondrial genes (two fragments of COI, 16S) and seven nuclear genes (ArgK, CAD, EF1α, enolase, H4, 18S, 28S). Analyses of maximum likelihood and Bayes inference recovered largely congruent results. Groups with different morphology of the rostral furrow (e.g. Aedemonini, Camptorhinini, Cryptorhynchini, Ithyporini) are not closely related to each other. However, most taxa with a mesosternal receptacle are monophyletic and here defined as Cryptorhynchinae s.s., comprising Cryptorhynchini, Gasterocercini, Torneumatini and Psepholacini, but also Arachnopodini and Idopelma Faust. The genus Phyrdenus LeConte is excluded from Cryptorhynchinae and transferred to Conotrachelini of Molytinae. Thus defined, the group still comprises several thousand species with centres of its diversity in South America and Australia. The early lineages we find in America and the Palearctic, while the extremely diverse faunas of Australia and neighbouring islands mainly belong to a more recent, species-rich radiation. This also includes a clade comprising the majority of litter-inhabiting species of New Zealand and the genus Miocalles Pascoe. Flightlessness was attained repeatedly and resulted in convergent evolution of a similar habitus in different zoogeographic regions, mainly exhibited by the polyphyletic genus Acalles Schoenherr.This work was funded by the Deutsche Forschungsgemenisnchaft, DFG (RI 1817/1-1, 3-1, 3-3)Peer Reviewe
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