Friday, June 23, 2017

Weekend reads

New reading material for the weekend or for those of you that are blessed with some better weather perhaps for Monday morning back at work. 


Bird remains that are difficult to identify taxonomically using morphological methods, are common in the palaeontological record. Other types of challenging avian material include artefacts and food items from endangered taxa, as well as remains from aircraft strikes. We here present a DNA-based method that enables taxonomic identification of bird remains, even from material where the DNA is heavily degraded. The method is based on the amplification and sequencing of two short variable parts of the 16S region in the mitochondrial genome. To demonstrate the applicability of this approach, we evaluated the method on a set of Holocene and Late Pleistocene postcranial bird bones from several palaeontological and archaeological sites in Europe with good success.

Community-level data, the type generated by an increasing number of metabarcoding studies, is often graphed as stacked bar charts or pie graphs that use color to represent taxa. These graph types do not convey the hierarchical structure of taxonomic classifications and are limited by the use of color for categories. As an alternative, we developed metacoder, an R package for easily parsing, manipulating, and graphing publication-ready plots of hierarchical data. Metacoder includes a dynamic and flexible function that can parse most text-based formats that contain taxonomic classifications, taxon names, taxon identifiers, or sequence identifiers. Metacoder can then subset, sample, and order this parsed data using a set of intuitive functions that take into account the hierarchical nature of the data. Finally, an extremely flexible plotting function enables quantitative representation of up to 4 arbitrary statistics simultaneously in a tree format by mapping statistics to the color and size of tree nodes and edges. Metacoder also allows exploration of barcode primer bias by integrating functions to run digital PCR. Although it has been designed for data from metabarcoding research, metacoder can easily be applied to any data that has a hierarchical component such as gene ontology or geographic location data. Our package complements currently available tools for community analysis and is provided open source with an extensive online user manual.

Studying taxonomic and ecological diversity of phytoplankton assemblages is often difficult because morphological analysis cannot provide a complete description of their composition. Therefore, more robust and feasible approaches have to be chosen to elucidate the interactions between environmental and human pressures and phytoplankton assemblages. The Ocean Sampling Day (OSD) allowed collecting seawater samples from a wide range of oceanic regions including the Mediterranean Sea. In this study, a total of 754,167 V4-18S ribosomal DNA (rDNA) metabarcodes derived from 20 plankton samples collected at 19 sampling sites across the coastal areas of the Mediterranean Sea were analyzed to explore the relationships between phytoplankton assemblages' composition, sub-regional environmental features and human pressures. We reduced the whole set of autotroph plankton (1398 OTUs) to a smaller number of ecologically relevant entities (205 taxa) and used the latter for analysing the structure of phytoplankton assemblages. Chaetoceros was the only genus occurring in all the samples, while the number of taxa was maximum in the W Mediterranean. Based on the assigned OTUs, the structure of E Mediterranean phytoplankton was the most homogeneous. Further, phytoplankton assemblages from the three Mediterranean sub-regions (Western, Adriatic and Eastern) were significantly different (R=0.25, p=0.0136) based on Jaccard similarity. We also observed that phytoplankton diversity and human impact on marine ecosystems were not significantly related to each other based on Mantel's test.

Human impact on marine benthic communities has traditionally been assessed using visible morphological traits and has focused on the macrobenthos, whereas the ecologically important organisms of the meio- and microbenthos have received less attention. DNA metabarcoding offers an alternative to this approach and enables a larger fraction of the biodiversity in marine sediments to be monitored in a cost-efficient manner. Although this methodology remains poorly standardised and challenged by biases inherent to rRNA copy number variation, DNA extraction, PCR, and limitations related to taxonomic identification, it has been shown to be semi-quantitative and useful for comparing taxon abundances between samples. Here, we evaluate the effect of replicating genomic DNA extraction in order to counteract small scale spatial heterogeneity and improve diversity and community structure estimates in metabarcoding-based monitoring. For this purpose, we used ten technical replicates from three different marine sediment samples. The effect of sequence depth was also assessed, and in silico pooling of DNA extraction replicates carried out in order to maintain the number of reads constant. Our analyses demonstrated that both sequencing depth and DNA extraction replicates could improve diversity estimates as well as the ability to separate samples with different characteristics. We could not identify a "sufficient" replicate number or sequence depth, where further improvements had a less significant effect. Based on these results, we consider replication an attractive alternative to directly increasing the amount of sample used for DNA extraction and strongly recommend it for future metabarcoding studies and routine assessments of sediment biodiversity.

Terrestrial animals must have frequent contact with water to survive, implying that environmental DNA (eDNA) originating from those animals should be detectable from places containing water in terrestrial ecosystems. Aiming to detect the presence of terrestrial mammals using forest water samples, we applied a set of universal PCR primers (MiMammal, a modified version of fish universal primers) for metabarcoding mammalian eDNA. The versatility of MiMammal primers was tested in silico and by amplifying DNAs extracted from tissues. The results suggested that MiMammal primers are capable of amplifying and distinguishing a diverse group of mammalian species. In addition, analyses of water samples from zoo cages of mammals with known species composition suggested that MiMammal primers could successfully detect mammalian species from water samples in the field. Then, we performed an experiment to detect mammals from natural ecosystems by collecting five 500-ml water samples from ponds in two cool-temperate forests in Hokkaido, northern Japan. MiMammal amplicon libraries were constructed using eDNA extracted from water samples, and sequences generated by Illumina MiSeq were subjected to data processing and taxonomic assignment. We thereby detected multiple species of mammals common to the sampling areas, including deer (Cervus nippon), mouse (Mus musculus), vole (Myodes rufocanus), raccoon (Procyon lotor), rat (Rattus norvegicus) and shrew (Sorex unguiculatus). Many previous applications of the eDNA metabarcoding approach have been limited to aquatic/semiaquatic systems, but the results presented here show that the approach is also promising even for forest mammal biodiversity surveys.

Benthic communities are key components of aquatic ecosystems' biomonitoring. However, morphology-based species identifications remain a low-throughput, and sometimes ambiguous, approach. Despite metabarcoding methodologies have been applied for above-species taxa inventories in marine meiofaunal communities, a comprehensive approach providing species-level identifications for estuarine macrobenthic communities is still lacking. Here we report a combination of experimental and field studies that demonstrate the aptitude of cytochrome oxidase I (COI) metabarcoding to provide robust species-level identifications within a framework of high-throughput monitoring of estuarine macrobenthic communities. To investigate the ability to recover DNA barcodes from all species present in a bulk community DNA extract, we assembled experimentally 3 phylogenetically diverse communities, and used in each 4 different primer pairs to generate an equal number of different PCR products of the COI barcode region. Between 78 and 83% of the species in the tested communities were recovered through multi-primer high throughput sequencing (HTS). Two primer pairs were sufficient to attain these recovery rates. Subsequently, we compared morphology and metabarcoding-based approaches to determine the species composition of macrobenthos from four distinct sites of the Sado estuary, Portugal. Our results indicate that the species richness would be considerably underestimated if only morphological methods were used. Although further refinement is required for improving the efficiency and output of this approach, here we show the great aptitude of COI-multi-primer metabarcoding to provide high quality and auditable species identifications in macrobenthos monitoring.

Wednesday, June 21, 2017

2017 GBIF Ebbe Nielsen Challenge






For the third year GBIF is running its Ebbe Nielsen Challenge. Developers and data scientists have three months to create and submit tools capable of liberating species records from open data repositories for scientific discovery and reuse. Here some more details:

Background
This year's Challenge will seek to leverage the growth of open data policies among scientific journals and research funders, which require researchers to make the data underlying their findings publicly available. Adoption of these policies represents an important first step toward increasing openness, transparency and reproducibility across all scientific domains, including biodiversity-related research.

To abide by these requirements, researchers often deposit datasets in public open-access repositories. Potential users are then able to find and access the data through repositories as well as data aggregators like OpenAIRE and DataONE. Many of these datasets are already structured in tables that contain the basic elements of biodiversity information needed to build species occurrence records: scientific names, dates, and geographic locations, among others.

However, the practices adopted by most repositories, funders and journals do not yet encourage the use of standardized formats. This approach significantly limits the interoperability and reuse of these datasets. As a result, the wider reuse of data implied if not stated by many open data policies falls short, even in cases where open licensing designations (like those provided through Creative Commons) seem to encourage it.

The challenge
The 2017 GBIF Ebbe Nielsen Challenge seeks submissions that repurpose these datasets and adapting them into the Darwin Core Archive format (DwC-A), the interoperable and reusable standard that powers the publication of almost 800 million species occurrence records from the nearly 1,000 worldwide institutions now active in the GBIF network.

The 2017 Ebbe Nielsen Challenge will task developers and data scientists to create web applications, scripts or other tools that automate the discovery and extraction of relevant biodiversity data from open data repositories. Such tools might generate datasets ready for publication on GBIF.org by:

  • Automating searches of open data available in public repositories
  • Effectively mining the information needed to generate checklists, species occurrence and sampling-event datasets (e.g. scientific names, date and location of occurrence et al.) from datasets in these repositories
  • Mapping datasets’ column headings and/or contents with standardized Darwin Core terms
  • Routinely converting the reformatted data into Darwin Core archive formats ready for publication through GBIF.org

Friday, June 16, 2017

Weekend reads

Hot of the press - more reading material from the DNA barcoding community. Not as many as last week in which I had a lot of catch up to do. Nevertheless, very interesting reads.

Thirty-four species of Culicidae are present in the UK, of which 15 have been implicated as potential vectors of arthropod-borne viruses such as West Nile virus. Identification of mosquito feeding preferences is paramount to the understanding of vector-host-pathogen interactions which, in turn, would assist in the control of disease outbreaks. Results are presented on the application of DNA barcoding for vertebrate species identification in blood-fed female mosquitoes in rural locations. Blood-fed females (n = 134) were collected in southern England from rural sites and identified based on morphological criteria. Blood meals from 59 specimens (44%) were identified as feeding on eight hosts: European rabbit, cow, human, barn swallow, dog, great tit, magpie and blackbird. Analysis of the cytochrome c oxidase subunit I mtDNA barcoding region and the internal transcribed spacer 2 rDNA region of the specimens morphologically identified as Anopheles maculipennis s.l. revealed the presence of An. atroparvus and An. messeae. A similar analysis of specimens morphologically identified as Culex pipiens/Cx. torrentium showed all specimens to be Cx. pipiens (typical form). This study demonstrates the importance of using molecular techniques to support species-level identification in blood-fed mosquitoes to maximize the information obtained in studies investigating host feeding patterns.

We used a 227-bp fragment of the mitochondrial gene cytochrome oxidase I (DNA "barcode") in conjunction with morphological data to study specimens of the Neotropical genus Orthocomotis Dognin, 1906, acquired from natural history collections. We examined over 20 species of Orthocomotis from 17 localities in Colombia, Ecuador, and Peru. The analysis identified 32 haplotypes among the 62 specimens and found no haplotypes shared among species. The molecular study revealed not only the usefulness of short COI sequences in discriminating among Orthocomotis species but also showed distinctness of four clusters which correspond to those based on morphological (genitalia) characters. Moreover, the molecular results suggest the occurrence of rapid speciation in Orthocomotis. We hypothesize that this may be linked to the great biodiversity of potential host plants in Neotropical ecosystems.

Taxonomic identification of pollen has historically been accomplished via light microscopy but requires specialized knowledge and reference collections, particularly when identification to lower taxonomic levels is necessary. Recently, next-generation sequencing technology has been used as a cost-effective alternative for identifying bee-collected pollen; however, this novel approach has not been tested on a spatially or temporally robust number of pollen samples. Here, we compare pollen identification results derived from light microscopy and DNA sequencing techniques with samples collected from honey bee colonies embedded within a gradient of intensive agricultural landscapes in the Northern Great Plains throughout the 2010-2011 growing seasons. We demonstrate that at all taxonomic levels, DNA sequencing was able to discern a greater number of taxa, and was particularly useful for the identification of infrequently detected species. Importantly, substantial phenological overlap did occur for commonly detected taxa using either technique, suggesting that DNA sequencing is an appropriate, and enhancing, substitutive technique for accurately capturing the breadth of bee-collected species of pollen present across agricultural landscapes. We also show that honey bees located in high and low intensity agricultural settings forage on dissimilar plants, though with overlap of the most abundantly collected pollen taxa. We highlight practical applications of utilizing sequencing technology, including addressing ecological issues surrounding land use, climate change, importance of taxa relative to abundance, and evaluating the impact of conservation program habitat enhancement efforts.

BACKGROUND:
Claims abound that the Transvaal red milkwood, Mimusops zeyheri, indigenous to areas with tropical and subtropical commercial fruit trees and fruiting vegetables in South Africa, is relatively pest free owing to its copious concentrations of latex in the above-ground organs. On account of observed fruit fly damage symptoms, a study was conducted to determine whether M. zeyheri was a host to the notorious quarantined Mediterranean fruit fly (Ceratitis capitata).
RESULTS:
Fruit samples were kept for 16-21 days in plastic pots containing moist steam-pasteurised growing medium with tops covered with a mesh sheath capable of retaining emerging flies. Microscopic diagnosis of the trapped flies suggested that the morphological characteristics were congruent with those of C. capitata, which was confirmed through cytochrome c oxidase I (COI) gene sequence alignment with a 100% bootstrap value and 99% confidence probability when compared with those from the National Centre for Biotechnology Information database.
CONCLUSION:
This study demonstrated that M. zeyheri is a host of C. capitata. Therefore, C. capitata from infestation reservoirs of M. zeyheri fruit trees could be a major threat to the tropical and subtropical fruit industries in South Africa owing to the fruit-bearing nature of the new host.

International agreements mandate the expansion of Earth's protected-area network as a bulwark against the continued extinction of wild populations, species, and ecosystems. Yet many protected areas are underfunded, poorly managed, and ecologically damaged; the conundrum is how to increase their coverage and effectiveness simultaneously. Innovative restoration and rewilding programmes in Costa Rica's Area de Conservacion Guanacaste and Mozambique's Parque Nacional da Gorongosa highlight how degraded ecosystems can be rehabilitated, expanded, and woven into the cultural fabric of human societies. Worldwide, enormous potential for biodiversity conservation can be realized by upgrading existing nature reserves while harmonizing them with the needs and aspirations of their constituencies.

Seed dispersal constitutes a pivotal process in an increasingly fragmented world, promoting population connectivity, colonization and range shifts in plants. Unveiling how multiple frugivore species disperse seeds through fragmented landscapes, operating as mobile links, has remained elusive owing to methodological constraints for monitoring seed dispersal events. We combine for the first time DNA barcoding and DNA microsatellites to identify, respectively, the frugivore species and the source trees of animal-dispersed seeds in forest and matrix of a fragmented landscape. We found a high functional complementarity among frugivores in terms of seed deposition at different habitats (forest vs. matrix), perches (isolated trees vs. electricity pylons) and matrix sectors (close vs. far from the forest edge), cross-habitat seed fluxes, dispersal distances, and canopy-cover dependency. Seed rain at the landscape-scale, from forest to distant matrix sectors, was characterized by turnovers in the contribution of frugivores and source-tree habitats: open-habitat frugivores replaced forest-dependent frugivores, whereas matrix trees replaced forest trees. As a result of such turnovers, the magnitude of seed rain was evenly distributed between habitats and landscape sectors. We thus uncover key mechanisms behind 'biodiversity-ecosystem function' relationships, in this case, the relationship between frugivore diversity and landscape-scale seed dispersal. Our results reveal the importance of open-habitat frugivores, isolated fruiting trees, and anthropogenic perching sites (infrastructures) in generating seed dispersal events far from the remnant forest, highlighting their potential to drive regeneration dynamics through the matrix. This study helps to broaden the 'mobile link' concept in seed dispersal studies by providing a comprehensive and integrative view of the way in which multiple frugivore species disseminate seeds through real-world landscapes.

Thursday, June 15, 2017

Plants and climate change

Plants provide us with food, pastures for livestock, and places for recreation and wellbeing. They also directly and indirectly provide numerous invaluable ecosystem services such as water regulation, carbon sequestration and flood prevention. As a result, it is imperative that we understand how plant populations are responding to climate constraints now, and use that information to predict how they are likely to respond to climatic changes in the future.

In fact it might be very important to assess the persistence strategies of plants in any given habitat. Noting its mere presence does not paint a very useful picture as a species may be found in a particular area but that doesn't mean it is making much of a living there; it may, just, be making ends meet for the time being. An international group of ecologists tested the links between climate suitability and persistence strategies for nearly 100 populations of over 30 species of trees and herbs growing on 3 continents and 16 countries across the globe. Some of these data were gathered over the duration of a decade, allowing the researchers to identify emergent patterns linked to climate change with greater confidence.

What they found is that while many species are able to persist in less favourable climate conditions, those same species often do so by adopting last-stand strategies such as shrinking in size and temporarily suspending reproductive and vegetative growth. This merely helps them to survive and makes them more vulnerable to further changes and to disturbances such as wildfires or pest outbreaks. Many such disturbances are more likely today due to changing climates.

Not all plants have the life strategies to persist for extended periods of time in less favourable climates but our research is already helping to pinpoint those that do. One of the next steps is to design management strategies to help support these species and to safeguard the ecosystem services that they provide us.


Wednesday, June 14, 2017

Invasive species hotspots

Human-mediated transport beyond biogeographic barriers has led to the introduction and establishment of alien species in new regions worldwide. However, we lack a global picture of established alien species richness for multiple taxonomic groups. 

The number of established alien species varies across the world and it is where the most established alien species can be found and which factors influence their distribution. An international team created a database for eight animal and plant groups (mammals, birds, amphibians, reptiles, fishes, spiders, ants and vascular plants) that were found to occur in regions outside their original habitat. The study of the distribution of these species led the research team to identify 186 islands and 423 mainland regions in total thereby illustrating the global distribution of established alien species. 

The highest number of alien species can be found on islands and in the coastal regions of continents. The island of Hawaii was found to have the most alien species, followed by the north island of New Zealand and the small Sunda Islands of Indonesia. What these places have in common is that they are remote islands that used to be very isolated, lacking some taxa altogether, e.g. mammals. Today, these island regions are economically highly developed and maintain intense trade relationships with the mainlands. 

We found the number of alien species to be particularly high in densely populated areas as well as in economically highly developed ones. These factors increase the likelihood of humans introducing many new species to an area. This almost invariably results in the destruction of natural habitats, which in turn allows non-indigenous species to spread. Islands and coastal regions seem to be particularly vulnerable because they occupy leading roles in global overseas trade. There is yet another considerable risk besides the introduction of new alien species. Many of the alien plants and animals that, until now, have been kept in people's homes and gardens and are not yet to be found in the wild might well spread in the future. Given the word-wide effects of climate change, this is in fact a distinct possibility.




Tuesday, June 13, 2017

Wide-Open

Number of samples in the NCBI GEO
Open data is a vital pillar of open science and a key enabler for reproducibility, data reuse, and novel discoveries. Enforcement of open-data policies, however, largely relies on manual efforts, which invariably lag behind the increasingly automated generation of biological data.

Researchers routinely deposit data in online repositories. But they are only human and its not rare that they forget to inform a repository to release their data once a paper is published. Open data is a vital pillar of open science, enabling other researchers to reproduce results and use the same datasets to produce novel discoveries. While many scientific journals now require published authors to make the data underlying their findings publicly available, these policies often go unenforced. The challenge is substantial -- the National Center for Biotechnology Information (NCBI) Gene Expression Omnibus repository (GEO) alone contains 80,985 public datasets, spanning hundreds of tissue types in thousands of organisms -- and the rapid growth in data makes it difficult for journals or data repositories to "police" whether datasets that should be made publicly available actually are.

A new tool, developed by University of Washington and Microsoft researchers automatically identifies datasets overdue for public release by applying text mining to dataset references in published articles and parse query results from repositories to determine if the datasets remain private.  The system is called Wide-Open and is available under an open source license on GitHub.

The colleagues tested their tool on two popular data repositories maintained by the NCBI - GEO and the Sequence Read Archive (SRA) . Wide-Open identified a large number of overdue datasets, which spurred repository administrators to respond by releasing 400 datasets within one week.

Monday, June 12, 2017

Defying Muller's Ratchet?

Meloidogyne incognita in action
For most animal species sexual reproduction is favored over asexual reproduction. A proposed mechanism to explain this is Muller's ratchet which assumes that the genomes of an asexual population accumulate deleterious mutations in an irreversible manner. However, this negative effect may not be prevalent in organisms which, while they reproduce asexually, also undergo other forms of recombination. 

Root-knot nematodes (Meloidogyne spp.) exhibit a diversity of reproductive modes ranging from obligatory sexual to fully asexual reproduction. Intriguingly, the most widespread and devastating species to global agriculture are those that reproduce asexually, without meiosis.  Instead of hitting an evolutionary dead-end, these plant pests have a wider geographic range and can infect greater numbers of crops than sexual species. 

To investigate the reasons behind their success, researchers sequenced and assembled the genomes of the three most damaging root-knot nematodes and compared them to a sexual relative. The asexual genomes are large, with numerous duplicated regions resulting from past reproduction events where at least two individual genomes recently hybridized together. They detected signs of positive selection between these gene copies and confirmed functional divergence at the expression pattern level. The colleagues think that it is this peculiar hybrid genome structure that provide these nematodes with a potential for adaptation and plasticity and explains the paradoxical success in the absence of sex:

By analyzing and comparing their genomes, we provide large-scale evidence that these asexual nematodes underwent hybridization and are polyploid. Their duplicated hybrid genome architectures provide these nematodes with multi-copy genes showing diverged sequence and expression patterns where their sexual relatives have very closely related alleles. We suspect these multiple copies provide a reservoir to adapt to different environments and plant hosts, and constitute an evolutionary advantage over their sexual relatives (at least in the short term). Their intriguing parasitic success despite absence of sex could thus be due to their hybrid origin where they combined multiple genomes of adapted parasitic nematodes in one single species.

In addition, Transposable elements (TE) cover a ~1.7 times higher proportion of the genomes of the ameiotic asexual Meloidogyne compared to the sexual relative and might also participate in their plasticity. The intriguing parasitic success of asexually-reproducing Meloidogyne species could be partly explained by their TE-rich composite genomes, resulting from allopolyploidization events, and promoting plasticity and functional divergence between gene copies in the absence of sex and meiosis.

It becomes paramount to understand under what conditions these hybrids came to be. It is a scary thought that similar conditions could favor the rise of even more aggressive and devastating new hybrids.

Friday, June 9, 2017

Weekend reads

After a longer silence due to some changes in the job and travel I am slowly picking up posting duties. I have decided to move the barcoding paper suggestions to Friday and rename these posts. If you happen to have nothing else to do on the weekend or in case you need some good reads for a quite moment, here they are:

Wine is a complex beverage, comprising hundreds of metabolites produced through the action of yeasts and bacteria in fermenting grape must. Commercially, there is now a growing trend away from using wine yeast ( Saccharomyces ) starter cultures, towards the historic practice of uninoculated or "wild" fermentation, where the yeasts and bacteria associated with the grapes and/or winery perform the fermentation. It is the varied metabolic contributions of these numerous non- Saccharomyces species that are thought to impart complexity and desirable taste and aroma attributes to wild ferments in comparison to their inoculated counterparts. To map the microflora of spontaneous fermentation, metagenomic techniques were employed to characterize and monitor the progression of fungal species in five different wild fermentations. Both amplicon-based ribosomal DNA internal transcribed spacer (ITS) phylotyping and shotgun metagenomics were used to assess community structure across different stages of fermentation. While providing a sensitive and highly accurate means of characterizing the wine microbiome, the shotgun metagenomic data also uncovered a significant over-abundance bias in the ITS phylotyping abundance estimations for the common non- Saccharomyces wine yeast genus Metschnikowia . By identifying biases such as that observed for Metschnikowia , abundance mesurements from future ITS-phylotyping datasets can corrected to provide more accurate species representation. Ulitmtaely, as more shotgun metagenomic and single-strain de novo assemblies for key wine species become available, the accuracy of both ITS-amplicon and shotgun studies will greatly increase, providing a powerful methodology for deciphering the influence of the microbial community on the wine flavor and aroma.

Genetic barcodes of arctic medusae and meiobenthic cnidarians have uncovered a fortuitous connection between the medusa Plotocnide borealis Wagner, 1885 and the minute, mud-dwelling polyp Boreohydra simplex Westblad, 1937. Little to no sequence differences exist among independently collected samples identified as Boreohydra simplex and Plotocnide borealis, showing that the two different forms represent a single species that is henceforth known by the older name Plotocnide borealis Wagner, 1885. The polyp form has been observed to produce bulges previously hypothesized to be gonophores, and the results here are consistent with that view. Interestingly, the polyp has also been reported to produce egg cells in the epiderm, a surprising phenomenon that we document here for only the second time. Thus, P. borealis produces eggs in two different life stages, polyp and medusa. This is the first documented case of a metagenetic medusozoan species being able to produce gametes in both the medusa and polyp stage. It remains unclear what environmental/ecological conditions modulate the production of eggs and/or medusa buds in the polyp stage. Similarly, sperm production, fertilization and development are unknown, warranting further studies.

The mosquito family (Diptera: Culicidae) constitutes the most medically important group of arthropods because certain species are vectors of human pathogens. In some parts of the world, the diversity is so high that the accurate delimitation and/or identification of species is challenging. A DNA-based identification system for all animals has been proposed, the so-called DNA barcoding approach. In this study, our objectives were (i) to establish DNA barcode libraries for the mosquitoes of French Guiana based on the COI and the 16S markers, (ii) to compare distance-based and tree-based methods of species delimitation to traditional taxonomy, and (iii) to evaluate the accuracy of each marker in identifying specimens. A total of 266 specimens belonging to 75 morphologically identified species or morphospecies were analyzed allowing us to delimit 86 DNA clusters with only 21 of them already present in the BOLD database. We thus provide a substantial contribution to the global mosquito barcoding initiative. Our results confirm that DNA barcodes can be successfully used to delimit and identify mosquito species with only a few cases where the marker could not distinguish closely related species. Our results also validate the presence of new species identified based on morphology, plus potential cases of cryptic species. We found that both COI and 16S markers performed very well, with successful identifications at the species level of up to 98% for COI and 97% for 16S when compared to traditional taxonomy. This shows great potential for the use of metabarcoding for vector monitoring and eco-epidemiological studies.

Molecular sequences in public databases are mostly annotated by the submitting authors without further validation. This procedure can generate erroneous taxonomic sequence labels. Mislabeled sequences are hard to identify, and they can induce downstream errors because new sequences are typically annotated using existing ones. Furthermore, taxonomic mislabelings in reference sequence databases can bias metagenetic studies which rely on the taxonomy. Despite significant efforts to improve the quality of taxonomic annotations, the curation rate is low because of the labor-intensive manual curation process. Here, we present SATIVA, a phylogeny-aware method to automatically identify taxonomically mislabeled sequences ('mislabels') using statistical models of evolution. We use the Evolutionary Placement Algorithm (EPA) to detect and score sequences whose taxonomic annotation is not supported by the underlying phylogenetic signal, and automatically propose a corrected taxonomic classification for those. Using simulated data, we show that our method attains high accuracy for identification (96.9% sensitivity/91.7% precision) as well as correction (94.9% sensitivity/89.9% precision) of mislabels. Furthermore, an analysis of four widely used microbial 16S reference databases (Greengenes, LTP, RDP and SILVA) indicates that they currently contain between 0.2% and 2.5% mislabels. Finally, we use SATIVA to perform an in-depth evaluation of alternative taxonomies for Cyanobacteria. SATIVA is freely available at https://github.com/amkozlov/sativa.

1. In recent years, large-scale DNA barcoding campaigns have generated an enormous amount of COI barcodes, which are usually stored in NCBI's GenBank and the official Barcode of Life database (BOLD). BOLD data are generally associated with more detailed and better curated meta-data, because a great proportion is based on expert-verified and vouchered material, accessible in public collections. In the course of the initiative German Barcode of Life (GBOL), data were generated for the reference library of 2,846 species of Coleoptera from 13,516 individuals.
2. Confronted with the high effort associated with the identification, verification and data validation, a bioinformatic pipeline, “TaxCI” was developed that i) identifies taxonomic inconsistencies in a given tree topology (optionally including a reference data set), ii) discriminates between different cases of incongruence in order to identify contamination or misidentified specimens, iii) graphically marks those cases in the tree, which finally can be checked again and, if needed, corrected or removed from the dataset. For this, “TaxCI” may use DNA-based species delimitations from other approaches (e.g., mPTP) or may perform implemented threshold-based clustering.
3. The data-processing pipeline was tested on a newly generated set of barcodes, using the available BOLD records as a reference. A data revision based on the first run of the TaxCI tool resulted in the second TaxCI analysis in a taxonomic match ratio very similar to the one recorded from the reference set (92 vs 94%). The revised dataset improved by nearly 20% through this procedure compared to the original, uncorrected one.
4. Overall, the new processing pipeline for DNA barcode data allows for the rapid and easy identification of inconsistencies in large datasets, which can be dealt with before submitting them to public data repositories like BOLD or GenBank. Ultimately, this will increase the quality of submitted data and the speed of data submission, while primarily avoiding the deterioration of the accuracy of the data repositories due to ambiguously identified or contaminated specimens.

Food trade globalization and the growing demand for selected food varieties have led to the intensification of adulteration cases, especially in the form of species substitution/mixing with cheaper taxa. This phenomenon acquired huge economic impact and sometimes even public health implications. DNA barcoding represents a well-proven molecular tool to assess the authenticity of food items, although its diffusion is hampered by analytical constraints and timeframes that are often prohibitive for food market. To address such issues, we have introduced a new technology, named NanoTracer, which allows for rapid and naked-eye molecular traceability of any food, employing limited instrumentation and cost-effective reagents. Moreover, unlike sequencing, this method allows to identify not only the substitution of a fine ingredient, but also its dilution with cheaper ones.

In this study, we used several molecular techniques to develop a fast and reliable protocol (DNA Verity Test, DVT) for the characterization and confirmation of the species or taxa present in herbal infusions. As a model plant for this protocol, Camellia sinensis, a traditional tea plant, was selected due to the following reasons: its historical popularity as a (healthy) beverage, its high selling value, the importation of barely recognizable raw product (i.e., crushed), and the scarcity of studies concerning adulterants or contamination. The DNA Verity Test includes both the sequencing of DNA barcoding markers and genotyping of labeled-PCR DNA barcoding fragments for each sample analyzed. This protocol (DVT) was successively applied to verify the authenticity of 32 commercial teas (simple or admixture), and the main results can be summarized as follows: (1) the DVT protocol is suitable to detect adulteration in tea matrices (contaminations or absence of certified ingredients), and the method can be exported for the study of other similar systems; (2) based on the BLAST analysis of the sequences of rbcL+matK±rps7-trnV(GAC) chloroplast markers, C. sinensis can be taxonomically characterized; (3) rps7-trnV(GAC) can be employed to discriminate C. sinensis from C. pubicosta; (4) ITS2 is not an ideal DNA barcode for tea samples, reflecting potential incomplete lineage sorting and hybridization/introgression phenomena in C. sinensis taxa; (5) the genotyping approach is an easy, inexpensive and rapid pre-screening method to detect anomalies in the tea templates using the trnH(GUG)-psbA barcoding marker; (6) two herbal companies provided no authentic products with a contaminant or without some of the listed ingredients; and (7) the leaf matrices present in some teabags could be constituted using an admixture of different C. sinensis haplotypes and/or allied species (C. pubicosta).

A large-scale comprehensive reference library of DNA barcodes for European marine fishes was assembled, allowing the evaluation of taxonomic uncertainties and species genetic diversity that were otherwise hidden in geographically restricted studies. A total of 4118 DNA barcodes were assigned to 358 species generating 366 Barcode Index Numbers (BIN). Initial examination revealed as much as 141 BIN discordances (more than one species in each BIN). After implementing an auditing and five-grade (A-E) annotation protocol, the number of discordant species BINs was reduced to 44 (13% grade E), while concordant species BINs amounted to 271 (78% grades A and B) and 14 other had insufficient data (grade D). Fifteen species displayed comparatively high intraspecific divergences ranging from 2·6 to 18·5% (grade C), which is biologically paramount information to be considered in fish species monitoring and stock assessment. On balance, this compilation contributed to the detection of 59 European fish species probably in need of taxonomic clarification or re-evaluation. The generalized implementation of an auditing and annotation protocol for reference libraries of DNA barcodes is recommended.

Thursday, June 8, 2017

Kickstarter campaign

Save Coral Reefs: Costa Rica Calling

Have you ever heard of the Area de Conservacion Guanacaste (ACG)? As an ecologist or conservation biologist you might have, as a barcoder it is very likely you have. Home to 2.4% of the world’s terrestrial biodiversity, the ACG in Costa Rica is the only protected area in the Neotropics that sweeps from Pacific Ocean waters up over the volcanic mountain range of the continental divide and down into the lowlands of the Atlantic rain forest. In the mid-1980s, world renowned ecologist Dan Janzen and his wife and research partner, Winnie Hallwachs, had grown so alarmed at the rapid rate at which forests were disappearing in the region that they threw themselves into an immense conservation project, co-founded the ACG, and pretty much dedicated all their life to turn an area of 120,000 terrestrial hectares and 43,000 marine hectares into permanently conserved, government-owned, and managed wildlands. The ACG has also been the stage for a lot of groundbreaking work on DNA barcoding starting with the famous case of Astraptes fulgerator which was followed by numerous studies focusing on different aspects of the region and its biodiversity. Dan and Winnie are likely the strongest supporters of DNA barcoding outside our institute and a lot of the success of the past decade can be attributed to their tireless efforts to spread the word and convince colleagues of the value of DNA-based biodiversity research. When I was asked to spread the word about a Kickstarter campaign to support a new research project on corals in the ACG's marine sector there was no hesitation to provide some modest help through posting my blog:

video






Monday, May 15, 2017

From the inbox - metabarcoding course in Russia

International course in DNA Metabarcoding: Part 1 – Field collecting and Molecular laboratory.

Tromsø Museum (University of Tromsø, Norway), Forest Research Institute, Karelian Centre, Russian Academy of Sciences (Petrozavodsk, Russia), ForBio (Research School in Biosystematics), and SIU (Norwegian Centre for International Cooperation in Education) jointly offer an International Course in DNA Metabarcoding. The course will link its teaching program to the current research projects at the partner institutes to strengthen the connection between education and cutting age research methodologies by taking students through consecutive stages of the research process such as field collecting, plant community descriptions, laboratory set up and bioinformatic data analyses.

Time and place:  Aug. 7, 2017 9:30 AM - Aug. 19, 2017 4:30 PM, Forest Research Institute, Karelian Centre, Russian Academy of Sciences (Petrozavodsk, Russia).

DNA metabarcoding is a rapid method of biodiversity assessment utilizing environmental DNA (DNA obtained from sediments, soils, water, etc) which combines two technologies: DNA based species identification and high-throughput DNA sequencing. We include applications of DNA metabarcoding to ancient and recent plant community or species composition assessment using lake sediments as well as in diet study of the reindeer - one of the last remnants of the Beringian megafauna in the Arctic, keystone species, with high cultural and economic value for indigenous residents. The field collecting will be done in Karelia and Murmansk region of Russia, the laboratory work will be partially conducted in the field as well as using molecular laboratory facilities at the UiT. The computer classes for data processing and bioinformatic analyses will be held at the Tromsø Museum. The Tromsø-based Part 2 of the course will be organized in February 2018 and announced later. The detailed schedule of the programme including field work itinerary is upcoming.

Teachers:
Charlotte Clarke, University of Southampton, U.K.;
Eric Coissac, Laboratoire d’Écologie Alpine, Grenoble, France (Part 2: Data processing and Bioinformatics);
Galina Gusarova, Tromsø museum, University of Tromsø, Norway;
Stefaniya Kamenova, Centre for Ecological and Evolutionary Synthesis, University of Oslo, Norway;
Alexey Kravchenko Forest Research Institute, Karelian Centre, Russian Academy of Sciences, Petrozavodsk, Russia;

Financial aid: Only students affiliated with the universities from the partner countries in the High North Programme (Norway, Canada, China, Japan, Russia and U.S.A.) may be funded through the project funds. All expenses of the participants from the partner countries, including travel, accommodation, meals and bench fee are fully covered. Other applicants will have to cover return travel to St Petersburg (Russia). Additional expenses, including the local train tickets as well as food and lodging at two nature reserves, amount to 660 EUR in total. This amount will have to be transferred to the Tromsø Museum, University of Tromsø, before 1 July 2017, as we will book travel within Russia for all the participants together.

Registration: please fill out the online application form

Maximum number of participants is 15.
Application deadline is June 1, 2017.
The results will be announced by e-mail on June 8, 2017.

Please contact Galina Gusarova for more information.

Friday, May 5, 2017

From the inbox

Online questionnaire on the openness and ethics of data in life sciences

Dear colleague,

I need your help.

I am doing a study with my colleague Dimitris Damalas on the openness and ethics of data in life sciences. Thus we have prepared an online questionnaire

The objective of this questionnaire is to gain a better understanding of what researchers think on sharing and archiving, as well as barriers to the sharing and archiving of research data. The results of this survey will be published in a special issue on ‘The ethics and practice of openness in life science data’ of the international journal of Ethics in Science and Environmental Politics (Editors: Konstantinos Stergiou, Dimitrios Damalas).

The questionnaire takes less than 5 min to fill it. Can you please devote these 5 min and fill it?

Thank you in advance.

Prof. Kostas Stergiou

Director of the Institute of Marine Biological Resources and Inland Waters
Hellenic Center for Marine Research, Athens - Greece
Department of Biology
Aristotle University, Thessaloniki - Greece

Friday, April 28, 2017

Last chance - submit your abstract today

TODAY THE ABSTRACT DEADLINE ENDS


The African Centre for DNA Barcoding (ACDB), the University of  Johannesburg (UJ), International Barcode of Life Project (iBOL), and the Department of Environmental Affairs (DEA) are proud to announce and welcome delegates to our hosting of the 7th International Barcode of Life Conference, 20 – 24 November 2017. This is the first time that this event will be held on the African continent. The venue for the hosting of this prestigious event will be the Nombolo Mdhluli Conference Centre,
Skukuza.


The major theme of the conference is exploring mega-diverse biotas with DNA barcodes. A series of presentations and workshops will focus on the use of DNA to understand diversity patterns and ecological processes in species-rich and complicated ecosystems. The conference also provides a
general forum for presentations, posters, and discussion on the wider field of DNA barcoding.
Delegates are encouraged to register as soon as possible as space is limited.
Abstracts should be submitted here today.

More information at:
Website: http://dnabarcodes2017.org
Facebook: @DNABarcodes2017
Twitter: @DNABarcodes


Tuesday, April 25, 2017

Tuesday reads

Happy DNA Day! Has been a little while since the last post but I have been busy with a lot of different tasks and working myself into new projects. Here is hope that things will go back to normal slowly. Lots of interesting reads today starting with two of my own.

The School Malaise Trap Program (SMTP) provides a technologically sophisticated and scientifically relevant educational experience that exposes students to the diversity of life, enhancing their understanding of biodiversity while promoting environmental stewardship. Since 2013, the SMTP has allowed 15,000 students at 350 primary and secondary schools to explore insect diversity in Canadian schoolyards. Students at each school collected hundreds of insects for an analysis of DNA sequence variation that enabled their rapid identification to a species. Through this hands-on approach, they participated in a learning exercise that conveys a real sense of scientific discovery. As well, the students contributed valuable data to the largest biodiversity genomics initiative ever undertaken: the International Barcode of Life project. To date, the SMTP has sequenced over 80,000 insect specimens, which includes representatives of 7,990 different species, nearly a tenth of the Canadian fauna. Both surprisingly and importantly, the collections generated the first DNA barcode records for 1,288 Canadian species.

To date the global initiative to barcode all fishes, FISH-BOL, has delivered barcodes for approximately 14,400 of the 30,000 fish species; there is still much to do to attain its ultimate goal of barcoding all the world’s fishes. One strategy to overcome local gaps is to initiate short but intensive efforts to collect and barcode as many species as possible from a small region – a barcode ‘blitz’. This study highlights one such event, for the marine waters around Lizard island in the Great Barrier Reef (Queensland, Australia). Barcode records were obtained from 983 fishes collected over a two-week period. The resulting dataset comprised 358 named species and another 13 species that presently can only be reliably identified to genus level. Overall, this short expedition provided DNA barcodes for 13% of all marine fish species known to occur in Queensland.

The difficulty of censusing marine animal populations hampers effective ocean management. Analyzing water for DNA traces shed by organisms may aid assessment. Here we tested aquatic environmental DNA (eDNA) as an indicator of fish presence in the lower Hudson River estuary. A checklist of local marine fish and their relative abundance was prepared by compiling 12 traditional surveys conducted between 1988–2015. To improve eDNA identification success, 31 specimens representing 18 marine fish species were sequenced for two mitochondrial gene regions, boosting coverage of the 12S eDNA target sequence to 80% of local taxa. We collected 76 one-liter shoreline surface water samples at two contrasting estuary locations over six months beginning in January 2016. eDNA was amplified with vertebrate-specific 12S primers. Bioinformatic analysis of amplified DNA, using a reference library of GenBank and our newly generated 12S sequences, detected most (81%) locally abundant or common species and relatively few (23%) uncommon taxa, and corresponded to seasonal presence and habitat preference as determined by traditional surveys. Approximately 2% of fish reads were commonly consumed species that are rare or absent in local waters, consistent with wastewater input. Freshwater species were rarely detected despite Hudson River inflow. These results support further exploration and suggest eDNA will facilitate fine-scale geographic and temporal mapping of marine fish populations at relatively low cost.

We report the discovery of a non-native gammarid, Gammarus fossarum (Koch, 1836) (Crustacea, Amphipoda), in UK rivers. Gammarus fossarum is a common freshwater gammarid in many parts of mainland Europe, but was previously considered absent from the UK. Gammarus fossarum was detected in a number of UK rivers following DNA metabarcoding of a mini-barcode region of the COI gene in macroinvertebrate kick samples, and environmental DNA (eDNA) from water and sediment samples. Subsequent morphological analysis and standard DNA barcoding showed that the species could be reliably identified and separated from Gammarus pulex (Linnaeus, 1758), the most dominant and widespread native freshwater gammarid in the UK. Our data demonstrate extensive geographical coverage of G. fossarum in the UK, spanning distant river catchments. At present there is no data to confirm the likely origin of G. fossarum’s introduction. Subsequent re-examination of historic archive material shows the species to have been present in the UK since at least 1964. This study is among the first to demonstrate the potential of eDNA metabarcoding for detection of new non-native species. 

Consumption of frog legs is increasing worldwide, with potentially dramatic effects for ecosystems. More and more functioning frog farms are reported to exist. However, due to the lack of reliable methods to distinguish farmed from wild-caught individuals, the origin of frogs in the international trade is often uncertain. Here, we present a new methodological approach to this problem. We investigated the isotopic composition of legally traded frog legs from suppliers in Vietnam and Indonesia. Muscle and bone tissue samples were examined for δ15N, δ13C, and δ18O stable isotope compositions, to elucidate the conditions under which the frogs grew up. We used DNA barcoding (16S rRNA) to verify species identities. We identified three traded species (Hoplobatrachus rugulosus, Fejervarya cancrivora and Limnonectes macrodon); species identities were partly deviating from package labeling. Isotopic values of δ15N and δ18O showed significant differences between species and country of origin. Based on low δ15N composition and generally little variation in stable isotope values, our results imply that frogs from Vietnam were indeed farmed. In contrast, the frogs from the Indonesian supplier likely grew up under natural conditions, indicated by higher δ15N values and stronger variability in the stable isotope composition. Our results indicate that stable isotope analyses seem to be a useful tool to distinguish between naturally growing and intensively farmed frogs. We believe that this method can be used to improve the control in the international trade of frog legs, as well as for other biological products, thus supporting farming activities and decreasing pressure on wild populations. However, we examined different species from different countries and had no access to samples of individuals with confirmed origin and living conditions. Therefore, we suggest improving this method further with individuals of known origin and history, preferably including samples of the respective nutritive bases.

Biological diversity is depleting at an alarming rate. Additionally, a vast amount of biodiversity still remains undiscovered. Taxonomy has been serving the purpose of describing, naming, and classifying species for more than 250 years. DNA taxonomy and barcoding have accelerated the rate of this process, thereby providing a tool for conservation practice. DNA barcoding and traditional taxonomy have their own inherent merits and demerits. The synergistic use of both methods, in the form of integrative taxonomy, has the potential to contribute to biodiversity conservation in a pragmatic timeframe and overcome their individual drawbacks. In this review, we discuss the basics of both these methods of biological identification- traditional taxonomy and DNA barcoding, the technical advances in integrative taxonomy, and future trends. We also present a comprehensive compilation of published examples of integrative taxonomy that refer to nine topics within biodiversity conservation. Morphological and molecular species limits were observed to be congruent in ~41% of the 58 source studies. The majority of the studies highlighted the description of cryptic diversity through the use of molecular data, whereas research areas like endemism, biological invasion, and threatened species were less discussed in the literature.

Effective vector and arbovirus surveillance requires timely and accurate screening techniques that can be easily upscaled. Next-generation sequencing (NGS) is a high-throughput technology that has the potential to modernise vector surveillance. When combined with DNA barcoding, it is termed 'metabarcoding'. The aim of our study was to establish a metabarcoding protocol to characterise pools of mosquitoes and screen them for virus. Pools contained 100 morphologically identified individuals, including one Ross River virus (RRV) infected mosquito, with three species present at different proportions: 1, 5, 94%. Nucleic acid extracted from both crude homogenate and supernatant was used to amplify a 269 bp section of the mitochondrial cytochrome c oxidase subunit I (COI) locus. Additionally, a 67 bp region of the RRV E2 gene was amplified from synthesised cDNA to screen for RRV. Amplicon sequencing was performed using an Illumina MiSeq, and bioinformatic analysis was performed using a DNA barcode database of Victorian mosquitoes. Metabarcoding successfully detected all mosquito species and RRV in every positive sample tested. The limits of species detection were also examined by screening a pool of 1000 individuals, successfully identifying the species and RRV from a single mosquito. The primers used for amplification, number of PCR cycles, and total number of individuals present all have effects on the quantification of species in mixed bulk samples. Based on the results, a number of recommendations for future metabarcoding studies are presented. Overall, metabarcoding shows great promise for providing a new alternative approach to screening large insect surveillance trap catches. 

The potential of DNA barcoding approaches to identify single species and characterize species compositions strongly depends on the marker choice. The prominent "Folmer region", a 648 basepair fragment at the 5' end of the mitochondrial CO1 gene, has been traditionally applied as a universal DNA barcoding region for metazoans. In order to find a suitable marker for biomonitoring odonates (dragonflies and damselflies), we here explore a new region of the CO1 gene (CO1B) for DNA barcoding in 51 populations of 23 dragonfly and damselfly species. We compare the "Folmer region", the mitochondrial ND1 gene (NADH dehydrogenase 1) and the new CO1 region with regard to (i) speed and reproducibility of sequence generation, (ii) levels of homoplasy and (iii) numbers of diagnostic characters for discriminating closely related sister taxa and populations. The performances of the gene regions regarding these criteria were quite different. Both, the amplification of CO1B and ND1 was highly reproducible and CO1B showed the highest potential for discriminating sister taxa at different taxonomic levels. In contrast, the amplification of the "Folmer region" using the universal primers was difficult and the third codon positions of this fragment have experienced nucleotide substitution saturation. Most important, exploring this new barcode region of the CO1 gene identified a higher discriminating power between closely related sister taxa. Together with the design of layered barcode approaches adapted to the specific taxonomic "environment", this new marker will further enhance the discrimination power at the species level.

Monday, April 24, 2017

From the inbox: Postdoc @ Kartzinel Lab at Brown

Position Title: Postdoctoral Research Associate in Environment and Society: Molecular Ecology/Conservation Biology

Location: Department of Ecology and Evolutionary Biology; Institute at Brown for Environment and Society, Brown University, Providence, Rhode Island, USA

Position Description: The Kartzinel Lab at Brown University is seeking a postdoctoral research associate in molecular ecology and conservation biology to collaborate on studies of the ecology and evolution of animal diets, especially in African savannas (http://www.kartzinellab.com/). The postdoctoral project will emphasize conceptual and analytical advances in our understanding of plant-herbivore, predator-prey, and/or host-microbe interaction networks using DNA- based analyses. These results will be placed in the context of manipulative field experiments, broad geographic gradients, and different land use histories in order to illuminate the biological processes that determine population and community dynamics in a changing world. The postdoc will have ample opportunities to integrate both field and lab-based research on wildlife in Kenya, and other potentially relevant field sites. The Department of Ecology and Evolutionary Biology and Institute at Brown for Environment and Society are home to a diverse community of scholars and world-class scientific resources.

Qualifications: The successful candidate will have a recent Ph.D. and relevant experience in molecular ecology, such as environmental DNA analysis, microbiome analyses, DNA (meta) barcoding, metagenomics, or related approaches. A strong interest in community ecology and conservation is required, and prior field experience is a plus. Responsibilities include: helping develop and coordinate laboratory and field research activities; data management; analysis of ecological and molecular data; publication of manuscripts and dissemination of results. Candidates should demonstrate strong communication skills and an ability to work both independently and collaboratively with groups from diverse backgrounds.

Applicants should submit: (1) a cover letter describing research interests, qualifications, and motivations, (2) a CV, and (3) contact information for three references. Applications will be reviewed starting May 12, 2017, and accepted until the position is filled. The ideal start date is September 2017, but flexible. The initial appointment will be for one year with an opportunity for extension based on satisfactory performance. Please contact Tyler Kartzinel directly with any questions.


Equal Employment Opportunity Statement: Brown University is committed to fostering a diverse and inclusive academic global community; as an EEO/AA employer, Brown considers applicants for employment without regard to, and does not discriminate on the basis of, gender, race, protected veteran status, disability, or any other legally protected status.

Tuesday, April 18, 2017

Metabarcoding and Metagenomics journal

Not too long ago I posted a call for participation at a questionnaire which solicited feedback and suggestions for a new open access journal focusing on metabarcoding and metagenomics. Today, just a few months later the journal out in the open and ready for submission:

Metabarcoding and Metagenomics (MBMG) is an innovative open access journal which facilitates the publication of articles on metabarcoding and metagenomics both in basic and applied context. The journal welcomes submissions representing all stages of the research cycle: data, models, methods, workflows, software, perspectives, opinions, and conventional research articles. The journal will consider manuscripts for publication related (but not limited) to the following topics: Environmental MBMG, Microbial MBMG, Applied MBMG (biomonitoring, quarantine, environmental assessment, nature conservation, eDNA, species invasions and others), and other emerging fields related to MBMG. Submissions of bioinformatic approaches to MBMG (algorithms, software) are also encouraged.

So, if you are currently working on a metabarcoding or metagenomics study and looking for a home for your publication you might want to consider this new option.


Thursday, April 13, 2017

FINAL CALL FOR ABSTRACTS

7th International Barcode of Life Conference, 20 – 24 November 2017 at Kruger National Park



**FINAL CALL FOR ABSTRACTS**

The African Centre for DNA Barcoding (ACDB), the University of  Johannesburg (UJ), International Barcode of Life Project (iBOL), and the Department of Environmental Affairs (DEA) are proud to announce and welcome delegates to our hosting of the 7th International Barcode of Life Conference, 20 – 24 November 2017. This is the first time that this event will be held on the African continent. The venue for the hosting of this prestigious event will be the Nombolo Mdhluli Conference Centre, 
Skukuza.

The major theme of the conference is exploring mega-diverse biotas with DNA barcodes. A series of presentations and workshops will focus on the use of DNA to understand diversity patterns and ecological processes in species-rich and complicated ecosystems. The conference also provides a 
general forum for presentations, posters, and discussion on the wider field of DNA barcoding.

Delegates are encouraged to register as soon as possible as space is limited.

Abstracts should be submitted here before or on 28th April 2017.

More information at:

Website: http://dnabarcodes2017.org
Facebook: @DNABarcodes2017
Twitter: @DNABarcodes

Wednesday, April 12, 2017

Wednesday reads

Two days delay and a lot to go through but I think I came up with a list of quite interesting reads:

Phlebotomine sand flies are haematophagous dipterans of primary medical importance. They represent the only proven vectors of leishmaniasis worldwide and are involved in the transmission of various other pathogens. Studying the ecology of sand flies is crucial to understand the epidemiology of leishmaniasis and further control this disease. A major limitation in this regard is that traditional morphological-based methods for sand fly species identifications are time-consuming and require taxonomic expertise. DNA metabarcoding holds great promise in overcoming this issue by allowing the identification of multiple species from a single bulk sample. Here, we assessed the reliability of a short insect metabarcode located in the mitochondrial 16S rRNA for the identification of Neotropical sand flies, and constructed a reference database for 40 species found in French Guiana. Then, we conducted a metabarcoding experiment on sand flies mixtures of known content and showed that the method allows an accurate identification of specimens in pools. Finally, we applied metabarcoding to field samples caught in a 1-ha forest plot in French Guiana. Besides providing reliable molecular data for species-level assignations of phlebotomine sand flies, our study proves the efficiency of metabarcoding based on the mitochondrial 16S rRNA for studying sand fly diversity from bulk samples. The application of this high-throughput identification procedure to field samples can provide great opportunities for vector monitoring and eco-epidemiological studies.

Translating the vast amounts of molecular barcodes from global surveys of microbial eukaryotes into ecological insight depends critically on a well-curated reference database with adequate taxonomic coverage. In this respect, the choanoflagellates resemble other eukaryotic lineages: reasonable coverage at higher taxonomic levels, but missing diversity at the species level. The acanthoecid (loricate) choanoflagellates are well-characterized morphologically, with over 115 species described, but less than 10% with any sequence data. Because lorica shape is species-specific, the acanthoecids represent an opportunity to link morphological with molecular data within a lineage of eukaryotes. To match morphospecies to sequences, we sampled the Kattegat and the Isefjord in Denmark in September 2014 and February 2015. We identified 45 morphospecies and sequenced ribosomal DNA of nine previously unsequenced species, roughly doubling the number of acanthoecid species with sequence data, including the first data representing five genera: Bicosta, Calliacantha, Cosmoeca, Crinolina and Pleurasiga. Our phylogenetic analysis is mainly congruent with morphology-based systematics. Five of the newly sequenced species match a previously unidentified barcode from Tara Oceans, providing access to the global distribution of species isolated from Danish waters. One species, Calliacantha natans, is the second most globally abundant choanoflagellate present in Tara Oceans. Our project translating new ribosomal DNA sequences to distributions of described species on a global scale supports the approach linking morphology to molecular barcodes for microbial eukaryote ecology.

Almost all plants in nature harbour fungi in their roots but the knowledge on distribution and the underlying principles of assemblage is still poorly developed for the root-associated fungi. In this study we analysed the root endophytic fungal communities associated with switchgrass, rosette grass, and pitch pine in the acidic, oligotrophic pine barrens ecosystem. A total of 434 fungal isolates were obtained from 600 root segments of 60 plant samples. DNA barcoding and morphological analyses identified 92 fungal species, which belong to 39 genera in six classes. Compared to other ecosystems, the pine barrens has a higher proportion of Leotiomycetes. The fungal community associated with pitch pine was significantly different from those associated with the grasses, while less difference was found between those associated with the two grasses. Our results suggest that edaphic factors and host specificity play a role in shaping root endophytic fungal community. This study also corroborates our previous finding that plant roots in the pine barrens are a rich reservoir of novel fungi.

BACKGROUND:
The introduction of exotic species can have serious consequences for marine ecosystems. On the shores of the Cantabrian Sea (North of Spain) there are no routine examinations of seaweeds that combine molecular and morphological methods for early detection of exotic species making it difficult to assess in the early stages their establishment and expansion processes as a result of anthropogenic activities (e.g., shipping and/or aquaculture).
METHODS:
In this work we used both morphological identification and molecular barcoding (COI-5P and rbcL genes) of red algae collected in Asturias, Bay of Biscay (Gijón and Candás harbours) and from the University of Oviedo's herbarium samples.
RESULTS:
The results confirmed the presence of exotic Asian seaweeds Pachymeniopsis gargiuli and Grateloupia turuturu Yamada on Cantabrian Sea shores. Several individuals of these species were fertile and developing cystocarps when collected, underlining the risk of possible expansion or continued establishment. This study constitutes the first report of the Asian P. gargiuli in this area of the Bay of Biscay.
CONCLUSIONS:
Here the presence of the exotic species of the Halymeniales P. gargiuli is confirmed. We hypothesize that this species may have been established some time ago as a cryptic introduction with G. turuturu in Galician shores. The detection of these species on the shores of the Cantabrian Sea is relevant since introductions of Pachymeniopsis species could have been overlooked on other European coasts, probably mixed with G. turuturu and P. lanceolata. Our results confirm one new alien seaweed species that has been detected using molecular methods (COI-5P region and rbcL genes barcoding) on North Atlantic shores: the Asian native P. gargiuli. This demonstrates that routine screening for early detection of exotic algae in the Cantabrian Sea can be used for risk assessment. Genetic barcoding should be done using both rbcL gene and COI-5P regions since, although COI-databases are still poorer in sequences and this inhibits successful outcomes in Grateloupia-related species identifications, it is nonetheless a useful marker for species-level identifications in seaweeds.

The difficulty of censusing marine animal populations hampers effective ocean management. Analyzing water for DNA traces shed by organisms may aid assessment. Here we tested aquatic environmental DNA (eDNA) as an indicator of fish presence in the lower Hudson River estuary. A checklist of local marine fish and their relative abundance was prepared by compiling 12 traditional surveys conducted between 1988–2015. To improve eDNA identification success, 31 specimens representing 18 marine fish species were sequenced for two mitochondrial gene regions, boosting coverage of the 12S eDNA target sequence to 80% of local taxa. We collected 76 one-liter shoreline surface water samples at two contrasting estuary locations over six months beginning in January 2016. eDNA was amplified with vertebrate-specific 12S primers. Bioinformatic analysis of amplified DNA, using a reference library of GenBank and our newly generated 12S sequences, detected most (81%) locally abundant or common species and relatively few (23%) uncommon taxa, and corresponded to seasonal presence and habitat preference as determined by traditional surveys. Approximately 2% of fish reads were commonly consumed species that are rare or absent in local waters, consistent with wastewater input. Freshwater species were rarely detected despite Hudson River inflow. These results support further exploration and suggest eDNA will facilitate fine-scale geographic and temporal mapping of marine fish populations at relatively low cost.