scholarly journals GenBank is a reliable resource for 21st century biodiversity research

2019 ◽  
Vol 116 (45) ◽  
pp. 22651-22656 ◽  
Author(s):  
Matthieu Leray ◽  
Nancy Knowlton ◽  
Shian-Lei Ho ◽  
Bryan N. Nguyen ◽  
Ryuji J. Machida

Traditional methods of characterizing biodiversity are increasingly being supplemented and replaced by approaches based on DNA sequencing alone. These approaches commonly involve extraction and high-throughput sequencing of bulk samples from biologically complex communities or samples of environmental DNA (eDNA). In such cases, vouchers for individual organisms are rarely obtained, often unidentifiable, or unavailable. Thus, identifying these sequences typically relies on comparisons with sequences from genetic databases, particularly GenBank. While concerns have been raised about biases and inaccuracies in laboratory and analytical methods, comparatively little attention has been paid to the taxonomic reliability of GenBank itself. Here we analyze the metazoan mitochondrial sequences of GenBank using a combination of distance-based clustering and phylogenetic analysis. Because of their comparatively rapid evolutionary rates and consequent high taxonomic resolution, mitochondrial sequences represent an invaluable resource for the detection of the many small and often undescribed organisms that represent the bulk of animal diversity. We show that metazoan identifications in GenBank are surprisingly accurate, even at low taxonomic levels (likely <1% error rate at the genus level). This stands in contrast to previously voiced concerns based on limited analyses of particular groups and the fact that individual researchers currently submit annotated sequences to GenBank without significant external taxonomic validation. Our encouraging results suggest that the rapid uptake of DNA-based approaches is supported by a bioinformatic infrastructure capable of assessing both the losses to biodiversity caused by global change and the effectiveness of conservation efforts aimed at slowing or reversing these losses.

Cells ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 1152 ◽  
Author(s):  
Emily A. O’Connor ◽  
Helena Westerdahl ◽  
Reto Burri ◽  
Scott V. Edwards

Birds are a wonderfully diverse and accessible clade with an exceptional range of ecologies and behaviors, making the study of the avian major histocompatibility complex (MHC) of great interest. In the last 20 years, particularly with the advent of high-throughput sequencing, the avian MHC has been explored in great depth in several dimensions: its ability to explain ecological patterns in nature, such as mating preferences; its correlation with parasite resistance; and its structural evolution across the avian tree of life. Here, we review the latest pulse of avian MHC studies spurred by high-throughput sequencing. Despite high-throughput approaches to MHC studies, substantial areas remain in need of improvement with regard to our understanding of MHC structure, diversity, and evolution. Recent studies of the avian MHC have nonetheless revealed intriguing connections between MHC structure and life history traits, and highlight the advantages of long-term ecological studies for understanding the patterns of MHC variation in the wild. Given the exceptional diversity of birds, their accessibility, and the ease of sequencing their genomes, studies of avian MHC promise to improve our understanding of the many dimensions and consequences of MHC variation in nature. However, significant improvements in assembling complete MHC regions with long-read sequencing will be required for truly transformative studies.


Author(s):  
Carla Bridget Milazzo ◽  
Katherine Grace Zulak ◽  
Mariano Jordi Muria-Gonzalez ◽  
Darcy Jones ◽  
Matthew Power ◽  
...  

Over the last decade, the microbiome has received increasing attention as a key factor in macroorganism fitness. Sustainable pest management requires an understanding of the complex microbial endophyte communities existing symbiotically within plants and the way synthetic pesticides interact with them. Fungal endophytes are known to benefit plant growth and fitness and may deter pests and diseases. Recent advances in high-throughput sequencing (HTS) have enabled integrative microbiome studies especially in agricultural contexts. Here we profile the fungal endophyte community in the phyllosphere of two barley (Hordeum vulgare) cultivars exposed to two systemic foliar fungicides using metabarcoding, a HTS tool that constructs community profiles from environmental DNA (eDNA). We studied the fungal nuclear ribosomal large subunit (LSU) D2 and ITS2 DNA markers through a bioinformatics pipeline introduced here. We found 88 and 128 unique amplicon sequence variants (ASVs) using the D2 and ITS2 metabarcoding assays, respectively. With principal coordinate analysis (PCoA) and PERMANOVA, ASV diversity did not change in response to barley cultivar or fungicide treatment, however the community structure of unsprayed plants did change between two collection times eight days apart. The workflow described here can be applied to other microbiome studies in agriculture and we hope it encourages further research into crop microbiomes to improve agroecosystem management.


2019 ◽  
Author(s):  
Elena Valsecchi ◽  
Jonas Bylemans ◽  
Simon J. Goodman ◽  
Roberto Lombardi ◽  
Ian Carr ◽  
...  

ABSTRACTMetabarcoding studies using environmental DNA (eDNA) and high throughput sequencing (HTS) are rapidly becoming an important tool for assessing and monitoring marine biodiversity, detecting invasive species, and supporting basic ecological research. Several barcode loci targeting teleost fish and elasmobranchs have previously been developed, but to date primer sets focusing on other marine megafauna, such as marine mammals have received less attention. Similarly, there have been few attempts to identify potentially ‘universal’ barcode loci which may be informative across multiple marine vertebrate Orders. Here we describe the design and validation of four new sets of primers targeting hypervariable regions of the vertebrate mitochondrial 12S and 16S rRNA genes, which have conserved priming sites across virtually all cetaceans, pinnipeds, elasmobranchs, boney fish, sea turtles and birds, and amplify fragments with consistently high levels of taxonomically diagnostic sequence variation. ‘In silico’ validation using the OBITOOLS software showed our new barcode loci outperformed most existing vertebrate barcode loci for taxon detection and resolution. We also evaluated sequence diversity and taxonomic resolution of the new barcode loci in 680 complete marine mammal mitochondrial genomes demonstrating that they are effective at resolving amplicons for most taxa to the species level. Finally, we evaluated the performance of the primer sets with eDNA samples from aquarium communities with known species composition. These new primers will potentially allow surveys of complete marine vertebrate communities in single HTS metabarcoding assessments, simplifying workflows, reducing costs, and increasing accessibility to a wider range of investigators.


2020 ◽  
Vol 97 (1) ◽  
Author(s):  
Terrence H Bell ◽  
Thomas Bell

ABSTRACT The fundamental niches of bacteria can be defined along many environmental axes, including temperature tolerance and resources consumed, while interactions with other organisms can constrain (e.g. competition) or enlarge (e.g. cross-feeding) realized niches. Organisms are often categorized as generalists or specialists, corresponding to broad or narrow niche requirements, which can then be linked to their functional role in an ecosystem. We show how these terms are applied to bacteria, make predictions about how the type and extent of generalism displayed by an organism relates to its functional potential and discuss the value of collecting different types of generalist bacteria. We believe that new approaches that take advantage of both high-throughput sequencing and environmental manipulation can allow us to understand the many types of generalism found within both cultivated and yet-to-be-cultivated bacteria.


2015 ◽  
Author(s):  
M.V. Cannon ◽  
J. Hester ◽  
A. Shalkhauser ◽  
E.R. Chan ◽  
K. Logue ◽  
...  

Analysis of environmental DNA (eDNA) enables the detection of species of interest from water and soil samples, typically using species-specific PCR. Here, we describe a method to characterize the biodiversity of a given environment by amplifying eDNA using primer pairs targeting a wide range of taxa and high-throughput sequencing for species identification. We tested this approach on 91 water samples of 40 mL collected along the Cuyahoga River (Ohio, USA). We amplified eDNA using 12 primer pairs targeting mammals, fish, amphibians, birds, bryophytes, arthropods, copepods, plants and several microorganism taxa and sequenced all PCR products simultaneously by high-throughput sequencing. Overall, we identified DNA sequences from 15 species of fish, 17 species of mammals, 8 species of birds, 15 species of arthropods, one turtle and one salamander. Interestingly, in addition to aquatic and semiaquatic animals, we identified DNA from terrestrial species that live near the Cuyahoga River. We also identified DNA from one Asian carp species invasive to the Great Lakes but that had not been previously reported in the Cuyahoga River. Our study shows that analysis of eDNA extracted from small water samples using wide-range PCR amplification combined with high-throughput sequencing can provide a broad perspective on biological diversity.


2016 ◽  
Author(s):  
Rafal Gumienny ◽  
Dominik Jedlinski ◽  
Georges Martin ◽  
Arnau Vina-Villaseca ◽  
Mihaela Zavolan

Identification of long and short RNAs, their processing and expression patterns have been greatly facilitated by high-throughput sequencing. Frequently, these RNAs act as guides for ribonucleoprotein complexes that regulate the expression or processing of target RNAs. However, to determine the targets of the many newly discovered regulatory RNAs in high-throughput remains a challenge. To globally assign guide small nucleolar RNAs to site of 2'-O-ribose methylation in human cells, we here developed novel computational methods for the analysis of data that was generated with protocols designed to capture direct small RNA-target interactions and to identify the sites of 2'-O-ribose methylation genome-wide. We thereby determined that many "orphan" snoRNAs appear to guide 2'-O-ribose methylation at sites that are targeted by other snoRNAs and that snoRNAs can be reliably captured in interaction with many mRNAs, in which a subsequent 2'-O-methylation cannot be detected. Our study provides a reliable approach to the comprehensive characterization of snoRNA-target interactions in species beyond those in which these interactions have been traditionally studied and contribute to the rapidly developing field of "epitranscriptomics".


Author(s):  
Leho Tedersoo ◽  
Mads Albertsen ◽  
Sten Anslan ◽  
Benjamin Callahan

Short-read, high-throughput sequencing (HTS) methods have yielded numerous important insights into microbial ecology and function. Yet, in many instances short-read HTS techniques are suboptimal, for example by providing insufficient phylogenetic resolution or low integrity of assembled genomes. Single-molecule and synthetic long-read (SLR) HTS methods have successfully ameliorated these limitations. In addition, nanopore sequencing has generated a number of unique analysis opportunities such as rapid molecular diagnostics and direct RNA sequencing, and both PacBio and nanopore sequencing support detection of epigenetic modifications. Although initially suffering from relatively low sequence quality, recent advances have greatly improved the accuracy of long read sequencing technologies. In spite of great technological progress in recent years, the long-read HTS methods (PacBio and nanopore sequencing) are still relatively costly, require large amounts of high-quality starting material, and commonly need specific solutions in various analysis steps. Despite these challenges, long-read sequencing technologies offer high-quality, cutting-edge alternatives for testing hypotheses about microbiome structure and functioning as well as assembly of eukaryote genomes from complex environmental DNA samples.


Genes ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 530 ◽  
Author(s):  
Xie ◽  
Pan ◽  
Jiang ◽  
Liu ◽  
Lu ◽  
...  

Lactobacillus is a fairly diverse genus of bacteria with more than 260 species and subspecies. Many profiling methods have been developed to carry out phylogenetic analysis of this complex and diverse genus, but limitations remain since there is still a lack of comprehensive and accurate analytical method to profile this genus at species level. To overcome these limitations, a Lactobacillus-specific primer set was developed targeting a hypervariable region in the groEL gene—a single-copy gene that has undergone rapid mutation and evolution. The results showed that this methodology could accurately perform taxonomic identification of Lactobacillus down to the species level. Its detection limit was as low as 104 colony-forming units (cfu)/mL for Lactobacillus species. The assessment of detection specificity using the Lactobacillus groEL profiling method found that Lactobacillus, Pediococcus, Weissella, and Leuconostoc genus could be distinguished, but non-Lactobacillus Genus Complex could not be detected. The groEL gene sequencing and Miseq high-throughput approach were adopted to estimate the richness and diversity of Lactobacillus species in different ecosystems. The method was tested using kurut (fermented yak milk) samples and fecal samples of human, rat, and mouse. The results indicated that Lactobacillus mucosae was the predominant gut Lactobacillus species among Chinese, and L. johnsonii accounted for the majority of lactobacilli in rat and mouse gut. Meanwhile, L. delbrueckii subsp. bulgaricus had the highest relative abundance of Lactobacillus in kurut. Thus, this groEL gene profiling method is expected to promote the application of Lactobacillus for industrial production and therapeutic purpose.


PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9821 ◽  
Author(s):  
Monika K. Reczuga ◽  
Christophe Victor William Seppey ◽  
Matthieu Mulot ◽  
Vincent E.J. Jassey ◽  
Alexandre Buttler ◽  
...  

Current projections suggest that climate warming will be accompanied by more frequent and severe drought events. Peatlands store ca. one third of the world’s soil organic carbon. Warming and drought may cause peatlands to become carbon sources through stimulation of microbial activity increasing ecosystem respiration, with positive feedback effect on global warming. Micro-eukaryotes play a key role in the carbon cycle through food web interactions and therefore, alterations in their community structure and diversity may affect ecosystem functioning and could reflect these changes. We assessed the diversity and community composition of Sphagnum-associated eukaryotic microorganisms inhabiting peatlands and their response to experimental drought and warming using high throughput sequencing of environmental DNA. Under drier conditions, micro-eukaryotic diversity decreased, the relative abundance of autotrophs increased and that of osmotrophs (including Fungi and Peronosporomycetes) decreased. Furthermore, we identified climate change indicators that could be used as early indicators of change in peatland microbial communities and ecosystem functioning. The changes we observed indicate a shift towards a more “terrestrial” community in response to drought, in line with observed changes in the functioning of the ecosystem.


2018 ◽  
Vol 84 (11) ◽  
Author(s):  
Jaime Aguayo ◽  
Céline Fourrier-Jeandel ◽  
Claude Husson ◽  
Renaud Ioos

ABSTRACTTechniques based on high-throughput sequencing (HTS) of environmental DNA have provided a new way of studying fungal diversity. However, these techniques suffer from a number of methodological biases which may appear at any of the steps involved in a metabarcoding study. Air is one of the most important environments where fungi can be found, because it is the primary medium of dispersal for many species. Looking ahead to future developments, it was decided to test 20 protocols, including different passive spore traps, spore recovery procedures, DNA extraction kits, and barcode loci. HTS was performed with the Illumina MiSeq platform targeting two subloci of the fungal internal transcribed spacer. Multivariate analysis and generalized linear models showed that the type of passive spore trap, the spore recovery procedure, and the barcode all impact the description of fungal communities in terms of richness and diversity when assessed by HTS metabarcoding. In contrast, DNA extraction kits did not significantly impact these results. Although passive traps may be used to describe airborne fungal communities, a study using specific real-time PCR and a mock community showed that these kinds of traps are affected by environmental conditions that may induce losses of biological material, impacting diversity and community composition results.IMPORTANCEThe advent of high-throughput sequencing (HTS) methods, such as those offered by next-generation sequencing (NGS) techniques, has opened a new era in the study of fungal diversity in different environmental substrates. In this study, we show that an assessment of the diversity of airborne fungal communities can reliably be achieved by the use of simple and robust passive spore traps. However, a comparison of sample processing protocols showed that several methodological biases may impact the results of fungal diversity when assessed by metabarcoding. Our data suggest that identifying these biases is of paramount importance to enable a correct identification and relative quantification of community members.


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