scholarly journals A novel metabarcoding primer pair for environmental DNA analysis of Cephalopoda (Mollusca) targeting the nuclear 18S rRNA region

2021 ◽  
Vol 8 (2) ◽  
pp. 201388
Author(s):  
Daniëlle S. W. de Jonge ◽  
Véronique Merten ◽  
Till Bayer ◽  
Oscar Puebla ◽  
Thorsten B. H. Reusch ◽  
...  
Keyword(s):  
18S Rrna ◽  
Dna Analysis ◽  
Hypervariable Region ◽  
Environmental Dna ◽  
Degraded Dna ◽  
Reference Database ◽  
Rrna Gene ◽  
Target Sequence ◽  
Universal Primer ◽  
Cephalopod Species

Cephalopods are pivotal components of marine food webs, but biodiversity studies are hampered by challenges to sample these agile marine molluscs. Metabarcoding of environmental DNA (eDNA) is a potentially powerful technique to study oceanic cephalopod biodiversity and distribution but has not been applied thus far. We present a novel universal primer pair for metabarcoding cephalopods from eDNA, Ceph18S (Forward: 5′-CGC GGC GCT ACA TAT TAG AC-3′, Reverse: 5′-GCA CTT AAC CGA CCG TCG AC-3′). The primer pair targets the hypervariable region V2 of the nuclear 18S rRNA gene and amplifies a relatively short target sequence of approximately 200 bp in order to allow the amplification of degraded DNA. In silico tests on a reference database and empirical tests on DNA extracts from cephalopod tissue estimate that 44–66% of cephalopod species, corresponding to about 310–460 species, can be amplified and identified with this primer pair. A multi-marker approach with the novel Ceph18S and two previously published cephalopod mitochondrial 16S rRNA primer sets targeting the same region (Jarman et al . 2006 Mol. Ecol. Notes. 6 , 268–271; Peters et al . 2015 Mar. Ecol. 36 , 1428–1439) is estimated to amplify and identify 89% of all cephalopod species, of which an estimated 19% can only be identified by Ceph18S . All sequences obtained with Ceph18S were submitted to GenBank, resulting in new 18S rRNA sequences for 13 cephalopod taxa.

dinoref : A curated dinoflagellate (Dinophyceae) reference database for the 18S rRNA gene

2018 ◽  
Vol 18 (5) ◽  
pp. 974-987 ◽  
Author(s):  
Solenn Mordret ◽  
Roberta Piredda ◽  
Daniel Vaulot ◽  
Marina Montresor ◽  
Wiebe H. C. F. Kooistra ◽  
...  
Keyword(s):  
18S Rrna ◽  
18S Rrna Gene ◽  
Reference Database ◽  
Rrna Gene

scholarly journals Short COI markers for freshwater macroinvertebrate metabarcoding

2017 ◽  
Author(s):  
Ecaterina Edith Vamos ◽  
Vasco Elbrecht ◽  
Florian Leese
Keyword(s):  
In Silico ◽  
Detection Efficiency ◽  
In Silico Analysis ◽  
Environmental Dna ◽  
Degraded Dna ◽  
Macroinvertebrate Communities ◽  
Universal Primer ◽  
Primer Sets ◽  
Mock Communities

Species diversity of metazoan bulk samples can be rapidly assessed using cytochrome c oxidase I (COI) metabarcoding. However, in some applications often only degraded DNA is available, e.g. from poorly conserved museum specimens, environmental DNA (eDNA) filtered from water or gut content analyses. Here universal primer sets targeting only a short COI fragment are advantageous, as they often can still amplify short DNA fragments. Using PrimerMiner, we optimised two universal primer sets targeting freshwater macroinvertebrates based on NCBI and BOLD reference sequences. The fwh1 and fwh2 primer sets targeting a 178 and 205 bp region were tested in vitro by sequencing previously used freshwater macroinvertebrate mock communities as well as three monitoring samples from Romanian streams of unknown composition. They were further evaluated in silico for their suitability to amplify other insect groups. The fwh1 primer sets showed the most consistent amplification in silico and in vitro , detecting 92% of the taxa present in the mock communities, and allowing clear differentiation between the three macroinvertebrate communities from the Romanian streams. In silico analysis indicates that the short primers are likely to perform well even for non-freshwater insects. Comparing the performance of the new fwh1 primer sets to a highly degenerate primer set targeting a longer fragment (BF2+BR2) revealed that detection efficiency is slightly lower for the new primer set. Nevertheless, the shorter new primer pairs might be useful for studies that have to rely on degraded or poorly conserved DNA and thus be of importance for biomonitoring, conservation biological or molecular ecological studies. Furthermore, our study highlights the need for in silico evaluation of primer sets in order to detect design errors in primers (fwhR2) and find optimal universal primer sets for the target taxa of interest.

scholarly journals Species, Sequence Types and Alleles: Dissecting Genetic Variation in Acanthamoeba

Pathogens ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 534
Author(s):  
Paul A. Fuerst ◽  
Gregory C. Booton
Keyword(s):  
Genetic Variation ◽  
18S Rrna ◽  
Hypervariable Region ◽  
18S Rrna Gene ◽  
Sequence Type ◽  
Rrna Gene ◽  
Dna Databases ◽  
Molecular Approaches ◽  
History Of ◽  
Sequence Types

Species designations within Acanthamoeba are problematic because of pleomorphic morphology. Molecular approaches, including DNA sequencing, hinted at a resolution that has yet to be fully achieved. Alternative approaches were required. In 1996, the Byers/Fuerst lab introduced the concept of sequence types. Differences between isolates of Acanthamoeba could be quantitatively assessed by comparing sequences of the nuclear 18S rRNA gene, ultimately producing 22 sequence types, designated T1 through T22. The concept of sequence types helps our understanding of Acanthamoeba evolution. Nevertheless, substantial variation in the 18S rRNA gene differentiates many isolates within each sequence type. Because the majority of isolates with sequences in the international DNA databases have been studied for only a small segment of the gene, designated ASA.S1, genetic variation within this hypervariable region of the 18S rRNA gene has been scrutinized. In 2002, we first categorized variation in this region in a sample of T3 and T4 isolates from Hong Kong, observing ten “alleles” within type T4 and five “alleles” within T3. Subsequently, confusion occurred when different labs applied redundant numerical labels to identify different alleles. A more unified approach was required. We have tabulated alleles occurring in the sequences submitted to the international DNA databases, and determined their frequencies. Over 150 alleles have occurred more than once within 3500+ isolates of sequence type T4. Results from smaller samples of other sequence types (T3, T5, T11 and T15, and supergroup T2/6) have also been obtained. Our results provide new insights into the evolutionary history of Acanthamoeba, further illuminating the degree of genetic separation between significant taxonomic units within the genus, perhaps eventually elucidating what constitutes a species of Acanthamoeba.

scholarly journals Phylogenetic information of freshwater copepod (Diaptomus sicilis) with special reference to 18S rRNA

2016 ◽  
Vol 4 (1) ◽  
pp. 25 ◽  
Author(s):  
Gomathi Jeyam Mookkaiah ◽  
Ramanibai Ravichandran
Keyword(s):  
Tamil Nadu ◽  
18S Rrna ◽  
Molecular Data ◽  
Small Subunit ◽  
18S Rrna Gene ◽  
Rrna Gene ◽  
Calanoid Copepods ◽  
Universal Primer ◽  
Pcr Products ◽  
The Individual

<p>In the present investigation to isolate freshwater calanoid copepods (<em>Diaptomus sicilis</em>) was characterized and identify the organisms by 18S rRNA sequencing. Plankton samples containing <em>D. sicilis</em> were collected during January 2014 (Post-monsoon) from Madippakkam Lake (12°57'41"N80°11'27"E) Chennai, Tamil Nadu. Immediately after sampling, specimens for genetic analyses were fixed in 95% ethyl alcohol. The total DNA was extracted from the individual copepod <em>D. sicilis</em> using Qiagen Blood tissue kit. The nuclear small subunit 18S rRNA gene was amplified using the Universal primer LCO —1490 (5’-GGTCAACAAATCATAAAGATATTGG-3’) and HCO-2198 (5’-TAAACTTCAGGGTGACCAAAAAATCA-3’). PCR products were loaded onto a 1% TAE agarose gel. Sequences were carried out an automated sequencer. The nucleotide sequence of 1282 base pair region of 18S rRNA was determined for D. sicilis. The similarity of sequences of <em>D. sicilis</em> was retrieved by BLASTn pro­gram and maximum identity and E-value was 76% and 0.00, respectively. The PCR products of <em>D. sicilis</em> individuals showed 80% similarity with the partial nuclear small subunit 18S rRNA gene region of other calanoid copepods. Based on molecular data the freshwater Calanoid copepods showed different algorithms and similar types of topologies useful for designing molecular analyses using phylogeny tree construction.Present molecular stud­ies on the relationship of D. sicilis with other freshwater calanoid copepods indicate that this species is close to <em>D. castor</em> followed by <em>D. keniraensis</em><em>.</em></p>

scholarly journals Design and Evaluation of Illumina MiSeq-Compatible, 18S rRNA Gene-Specific Primers for Improved Characterization of Mixed Phototrophic Communities

2016 ◽  
Vol 82 (19) ◽  
pp. 5878-5891 ◽  
Author(s):  
Ian M. Bradley ◽  
Ameet J. Pinto ◽  
Jeremy S. Guest
Keyword(s):  
Community Structure ◽  
18S Rrna ◽  
Target Genes ◽  
Hypervariable Region ◽  
Illumina Miseq ◽  
Amplicon Sequencing ◽  
18S Rrna Gene ◽  
Rrna Gene ◽  
Sequencing Bias ◽  
Primer Sets

ABSTRACTThe use of high-throughput sequencing technologies with the 16S rRNA gene for characterization of bacterial and archaeal communities has become routine. However, the adoption of sequencing methods for eukaryotes has been slow, despite their significance to natural and engineered systems. There are large variations among the target genes used for amplicon sequencing, and for the 18S rRNA gene, there is no consensus on which hypervariable region provides the most suitable representation of diversity. Additionally, it is unclear how much PCR/sequencing bias affects the depiction of community structure using current primers. The present study amplified the V4 and V8-V9 regions from seven microalgal mock communities as well as eukaryotic communities from freshwater, coastal, and wastewater samples to examine the effect of PCR/sequencing bias on community structure and membership. We found that degeneracies on the 3′ end of the current V4-specific primers impact read length and mean relative abundance. Furthermore, the PCR/sequencing error is markedly higher for GC-rich members than for communities with balanced GC content. Importantly, the V4 region failed to reliably capture 2 of the 12 mock community members, and the V8-V9 hypervariable region more accurately represents mean relative abundance and alpha and beta diversity. Overall, the V4 and V8-V9 regions show similar community representations over freshwater, coastal, and wastewater environments, but specific samples show markedly different communities. These results indicate that multiple primer sets may be advantageous for gaining a more complete understanding of community structure and highlight the importance of including mock communities composed of species of interest.IMPORTANCEThe quantification of error associated with community representation by amplicon sequencing is a critical challenge that is often ignored. When target genes are amplified using currently available primers, differential amplification efficiencies result in inaccurate estimates of community structure. The extent to which amplification bias affects community representation and the accuracy with which different gene targets represent community structure are not known. As a result, there is no consensus on which region provides the most suitable representation of diversity for eukaryotes. This study determined the accuracy with which commonly used 18S rRNA gene primer sets represent community structure and identified particular biases related to PCR amplification and Illumina MiSeq sequencing in order to more accurately study eukaryotic microbial communities.

scholarly journals MiFish, a set of universal PCR primers for metabarcoding environmental DNA from fishes: detection of more than 230 subtropical marine species

2015 ◽  
Vol 2 (7) ◽  
pp. 150088 ◽  
Author(s):  
M. Miya ◽  
Y. Sato ◽  
T. Fukunaga ◽  
T. Sado ◽  
J. Y. Poulsen ◽  
...  
Keyword(s):  
Fish Species ◽  
Survey Methods ◽  
Hypervariable Region ◽  
Environmental Dna ◽  
Pcr Primers ◽  
12S Rrna ◽  
Rrna Gene ◽  
Sufficient Information ◽  
Diverse Range ◽  
Spatial And Temporal Scales

We developed a set of universal PCR primers (MiFish-U/E) for metabarcoding environmental DNA (eDNA) from fishes. Primers were designed using aligned whole mitochondrial genome (mitogenome) sequences from 880 species, supplemented by partial mitogenome sequences from 160 elasmobranchs (sharks and rays). The primers target a hypervariable region of the 12S rRNA gene (163–185 bp), which contains sufficient information to identify fishes to taxonomic family, genus and species except for some closely related congeners. To test versatility of the primers across a diverse range of fishes, we sampled eDNA from four tanks in the Okinawa Churaumi Aquarium with known species compositions, prepared dual-indexed libraries and performed paired-end sequencing of the region using high-throughput next-generation sequencing technologies. Out of the 180 marine fish species contained in the four tanks with reference sequences in a custom database, we detected 168 species (93.3%) distributed across 59 families and 123 genera. These fishes are not only taxonomically diverse, ranging from sharks and rays to higher teleosts, but are also greatly varied in their ecology, including both pelagic and benthic species living in shallow coastal to deep waters. We also sampled natural seawaters around coral reefs near the aquarium and detected 93 fish species using this approach. Of the 93 species, 64 were not detected in the four aquarium tanks, rendering the total number of species detected to 232 (from 70 families and 152 genera). The metabarcoding approach presented here is non-invasive, more efficient, more cost-effective and more sensitive than the traditional survey methods. It has the potential to serve as an alternative (or complementary) tool for biodiversity monitoring that revolutionizes natural resource management and ecological studies of fish communities on larger spatial and temporal scales.

scholarly journals Investigating diversity of pathogenic microbes in commercial bait trade water

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5468 ◽  
Author(s):  
Andrew R. Mahon ◽  
Dean J. Horton ◽  
Deric R. Learman ◽  
Lucas R. Nathan ◽  
Christopher L. Jerde
Keyword(s):  
Great Lakes ◽  
Lake Michigan ◽  
Hypervariable Region ◽  
Environmental Dna ◽  
Taxonomic Diversity ◽  
Aquatic Systems ◽  
Rrna Gene ◽  
Great Lakes Region ◽  
Pathogen Diversity ◽  
Important Pathway

The recreational bait trade is a potential pathway for pathogen introduction and spread when anglers dump bait shop sourced water into aquatic systems. Despite this possibility, and previous recognition of the importance of the bait trade in the spread of aquatic invasive species (AIS), to date there has been no region wide survey documenting pathogens in retail bait shops. In this study, we analyzed 96 environmental DNA samples from retail bait shops around the Great Lakes region to identify pathogens, targeting the V4 hypervariable region of the 16S rRNA gene. Additionally, we used samples from one site in Lake Michigan as a comparison to pathogen diversity and abundance in natural aquatic systems. Our results identified nine different groups of pathogens in the bait shop samples, including those that pose risks to both humans and fish species. Compared to wild sourced samples, the bait shops had higher relative abundance and greater taxonomic diversity. These findings suggest that the bait trade represents a potentially important pathway that could introduce and spread pathogens throughout the Great Lakes region. Improving pathogen screening and angler outreach should be used in combination to aid in preventing the future spread of high risk pathogens.

scholarly journals Culturing and environmental DNA sequencing uncover hidden kinetoplastid biodiversity and a major marine clade within ancestrally freshwater Neobodo designis

2005 ◽  
Vol 55 (6) ◽  
pp. 2605-2621 ◽  
Author(s):  
Sophie von der Heyden ◽  
Thomas Cavalier-Smith
Keyword(s):  
Genetic Diversity ◽  
Dna Sequences ◽  
18S Rrna ◽  
Environmental Dna ◽  
Pcr Primers ◽  
Rrna Genes ◽  
Rrna Gene ◽  
Free Living ◽  
Marine Habitats ◽  
18S Rrna Genes

Bodonid flagellates (class Kinetoplastea) are abundant, free-living protozoa in freshwater, soil and marine habitats, with undersampled global biodiversity. To investigate overall bodonid diversity, kinetoplastid-specific PCR primers were used to amplify and sequence 18S rRNA genes from DNA extracted from 16 diverse environmental samples; of 39 different kinetoplastid sequences, 35 belong to the subclass Metakinetoplastina, where most group with the genus Neobodo or the species Bodo saltans, whilst four group with the subclass Prokinetoplastina (Ichthyobodo). To study divergence between freshwater and marine members of the genus Neobodo, 26 new Neobodo designis strains were cultured and their 18S rRNA genes were sequenced. It is shown that the morphospecies N. designis is a remarkably ancient species complex with a major marine clade nested among older freshwater clades, suggesting that these lineages were constrained physiologically from moving between these environments for most of their long history. Other major bodonid clades show less-deep separation between marine and freshwater strains, but have extensive genetic diversity within all lineages and an apparently biogeographically distinct distribution of B. saltans subclades. Clade-specific 18S rRNA gene primers were used for two N. designis subclades to test their global distribution and genetic diversity. The non-overlap between environmental DNA sequences and those from cultures suggests that there are hundreds, possibly thousands, of different rRNA gene sequences of free-living bodonids globally.

scholarly journals Phylogenetic Analysis of the Hypervariable Region of the 18S rRNA Gene of Cryptosporidium Oocysts in Feces of Canada Geese (Branta canadensis): Evidence for Five Novel Genotypes

2004 ◽  
Vol 70 (1) ◽  
pp. 452-458 ◽  
Author(s):  
Kristen L. Jellison ◽  
Daniel L. Distel ◽  
Harold F. Hemond ◽  
David B. Schauer
Keyword(s):  
Genetic Diversity ◽  
Phylogenetic Analysis ◽  
18S Rrna ◽  
Hypervariable Region ◽  
Pcr Amplification ◽  
The United States ◽  
18S Rrna Gene ◽  
Rrna Gene ◽  
Canada Geese ◽  
Pcr Products

ABSTRACT To assess genetic diversity in Cryptosporidium oocysts from Canada geese, 161 fecal samples from Canada geese in the United States were analyzed. Eleven (6.8%) were positive for Cryptosporidium spp. following nested PCR amplification of the hypervariable region of the 18S rRNA gene. Nine PCR products from geese were cloned and sequenced, and all nine diverged from previously reported Cryptosporidium 18S rRNA gene sequences. Five sequences were very similar or identical to each other but genetically distinct from that of Cryptosporidium baileyi; two were most closely related to, but genetically distinct from, the first five; and two were distinct from any other sequence analyzed. One additional sequence in the hypervariable region of the 18S rRNA gene isolated from a cormorant was identical to that of C. baileyi. Phylogenetic analysis provided evidence for new genotypes of Cryptosporidium species in Canada geese. Results of this study suggest that the taxonomy of Cryptosporidium species in geese is complex and that a more complete understanding of genetic diversity among these parasites will facilitate our understanding of oocyst sources and species in the environment.

scholarly journals Short COI markers for freshwater macroinvertebrate metabarcoding

2017 ◽  
Author(s):  
Ecaterina Edith Vamos ◽  
Vasco Elbrecht ◽  
Florian Leese
Keyword(s):  
In Silico ◽  
Detection Efficiency ◽  
In Silico Analysis ◽  
Environmental Dna ◽  
Degraded Dna ◽  
Macroinvertebrate Communities ◽  
Universal Primer ◽  
Primer Sets ◽  
Mock Communities

Species diversity of metazoan bulk samples can be rapidly assessed using cytochrome c oxidase I (COI) metabarcoding. However, in some applications often only degraded DNA is available, e.g. from poorly conserved museum specimens, environmental DNA (eDNA) filtered from water or gut content analyses. Here universal primer sets targeting only a short COI fragment are advantageous, as they often can still amplify short DNA fragments. Using PrimerMiner, we optimised two universal primer sets targeting freshwater macroinvertebrates based on NCBI and BOLD reference sequences. The fwh1 and fwh2 primer sets targeting a 178 and 205 bp region were tested in vitro by sequencing previously used freshwater macroinvertebrate mock communities as well as three monitoring samples from Romanian streams of unknown composition. They were further evaluated in silico for their suitability to amplify other insect groups. The fwh1 primer sets showed the most consistent amplification in silico and in vitro , detecting 92% of the taxa present in the mock communities, and allowing clear differentiation between the three macroinvertebrate communities from the Romanian streams. In silico analysis indicates that the short primers are likely to perform well even for non-freshwater insects. Comparing the performance of the new fwh1 primer sets to a highly degenerate primer set targeting a longer fragment (BF2+BR2) revealed that detection efficiency is slightly lower for the new primer set. Nevertheless, the shorter new primer pairs might be useful for studies that have to rely on degraded or poorly conserved DNA and thus be of importance for biomonitoring, conservation biological or molecular ecological studies. Furthermore, our study highlights the need for in silico evaluation of primer sets in order to detect design errors in primers (fwhR2) and find optimal universal primer sets for the target taxa of interest.

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