Find research datasets worth reusing
Search datasets from major research repositories and use ShareScore to quickly assess how well each record supports discovery, access, and reuse.
1,044
datasets available to search
ShareScore release 0.9.0
Dataset results
1,044 results for “pcr”
Performance evaluation of a laboratory developed PCR test for quantitation of HIV-2 viral RNA
Open the record for dataset details and reuse information.
Data from: Extensive allopolyploidy in the neotropical genus Lachemilla (Rosaceae) revealed by PCR ‐based target enrichment of the nuclear ribosomal DNA cistron and plastid phylogenomics
Open the record for dataset details and reuse information.
Droplet digital PCR (ddPCR) as a tool for investigating dynamics of cryptic symbionts
Open the record for dataset details and reuse information.
Data from: Comparative patterns of temporal decay and detectability of eDNA and eRNA across molecular markers in connected and isolated freshwater mesocosms using digital PCR
Open the record for dataset details and reuse information.
MicroRNA quantitative RT-PCR analysis of CMT1A Plasma
Open the record for dataset details and reuse information.
Data from: Digital PCR quantification of ultrahigh ERBB2 copy number identifies poor breast cancer survival after trastuzumab
Open the record for dataset details and reuse information.
Data from: Quantitative PCR primer design affects quantification of dsRNA-mediated gene knockdown
RNA interference (RNAi) is a powerful tool for studying functions of candidate genes in both model and non-model organisms and a promising technique for therapeutic applications. Successful application of this technique relies on the accuracy and reliability of methods used to quantify gene knockdown. With the limitation in the availability of antibodies for detecting proteins, quantitative PCR (qPCR) remains the preferred method for quantifying target gene knockdown after dsRNA treatment . We evaluated how qPCR primer binding site and target gene expression levels affect quantification of intact mRNA transcripts following dsRNA-mediated RNAi. The use of primer pairs targeting the mRNA sequence within the dsRNA target region failed to reveal a significant decrease in target mRNA transcripts for genes with low expression levels, but not for a highly expressed gene. By contrast, significant knockdown was detected in all cases with primer pairs targeting the mRNA sequence extending beyond the dsRNA target region, regardless of the expression levels of the target gene. Our results suggest that at least for genes with low expression levels, quantifying the efficiency of dsRNA-mediated RNAi with primers amplifying sequences completely contained in the dsRNA target region should be avoided due to the risk of false negative results. Instead, primer pairs extending beyond the dsRNA target region of the mRNA transcript sequences should be used for accurate and reliable quantification of silencing efficiency.
Data from quantitative real-time PCR of corticotropin-releasing hormone and glucocorticoid receptor in the hippocampus and hypothalamus of rats subjected to midline fluid percussion injury or control sham surgery.
<p>These files contain all data from quantitative real-time PCR of corticotropin-releasing hormone (CRH) and glucocorticoid receptor (GR) measured in the hippocampus and hypothalamus of male and female rats. Rats were randomly assigned to a treatment group before the initiation of the study. Rats received a control sham surgery or were subjected to midline fluid percussion injury to induce a diffuse traumatic brain injury. Tissue biopsies were collected at 7 days post-injury and analyzed via quantitative real-time PCR. </p> <p> </p>
SARS-CoV-2 PCR training
<p>***english version***</p> <p>These movies show the nucleic acid extraction process from swab samples followed by the PCR diagnostic for SARS-CoV-2, using commercially available kits. They were originally produced in the frame of a remote training given by the Robert Koch Institute in April 2020. Additional training materials are available here: <a href="https://gitlab.com/zig-covid-training/sars-cov-2_pcr_training">https://gitlab.com/zig-covid-training/sars-cov-2_pcr_training</a>.</p> <p> </p> <p>***version en française***</p> <p>Ces films montrent le processus d'extraction d'acides nucléiques à partir d'échantillons écouvillons suivi du diagnostic PCR pour le SRAS-CoV-2, à l'aide de kits disponibles dans le commerce. Ils ont été initialement produits dans le cadre d'une formation dispensée par l'Institut Robert Koch en avril 2020. Des matériel de formation supplémentaires sont disponibles ici: <a href="https://gitlab.com/zig-covid-training/sars-cov-2_pcr_training">https://gitlab.com/zig-covid-training/sars-cov-2_pcr_training</a>.</p> <p> </p> <p>***version en español***</p> <p>Estas películas muestran el proceso de extracción de ácido nucleico de hisopos seguido del diagnóstico por PCR para SARS-CoV-2, utilizando los kits disponibles en el mercado. Estas películas fueron producidas originalmente en el marco de una capacitación a distancia, impartida por Instituto Robert Koch en abril de 2020. Usted puede consultar el material de capacitación adicional aquí: <a href="https://gitlab.com/zig-covid-training/sars-cov-2_pcr_training">https://gitlab.com/zig-covid-training/sars-cov-2_pcr_training</a>.</p> <p> </p> <p>***русская версия***</p> <p>Эти фильмы показывают процесс экстракции нуклеиновой кислоты из образцов мазка с последующей диагностикой ПЦР на SARS-CoV-2 с использованием имеющихся в продаже наборов. Изначально они были созданы в рамках дистанционного обучения, проведенного Институтом Роберта Коха в апреле 2020 года. Дополнительные учебные материалы доступны здесь: <a href="https://gitlab.com/zig-covid-training/sars-cov-2_pcr_training">https://gitlab.com/zig-covid-training/sars-cov-2_pcr_training</a> <<a href="https://gitlab.com/zig-covid-training/sars-cov-2_pcr_training">https://gitlab.com/zig-covid-training/sars-cov-2_pcr_training</a>> . </p> <p>We acknowledge Anna Shin (Анна Шин) and Nur Tukhanova (Нур Туханова) for translation of the Russian subtitles.</p> <p> </p>
Data from: Browsed twig environmental DNA: diagnostic PCR to identify ungulate species
Ungulate browsing can have a strong effect on ecological processes by affecting plant community structure and composition, with cascading effects on nutrient cycling and animal communities. However, in the absence of direct observations of foraging, species-specific foraging behaviors are difficult to quantify. We therefore know relatively little about foraging competition and species specific browsing patterns in systems with several browsers. However, during browsing, a small amount of saliva containing buccal cells is deposited at the bite site, providing a source of environmental DNA (eDNA) that can be used for species identification. Here we describe extraction and PCR protocols for a browser species diagnostic kit. Species specific primers for mitochondrial DNA were optimized and validated using twigs browsed by captive animals. A time series showed that about 50% of the samples will amplify up to 12 weeks after the browsing event, and that some samples amplify up to 24 weeks after browsing (12.5%). Applied to samples of natural browsing from an area where moose (Alces alces), roe deer (Capreolus capreolus), fallow deer (Cervus dama), and red deer (Cervus elaphus) are sympatric, amplification success reached 75%. This method promises to greatly improve our understanding of multispecies browsing systems without the need for direct observations.
Data from: Collecting in collections: a PCR strategy and primer set for DNA barcoding of decades-old dried museum specimens
Natural history museums are vastly underutilized as a source of material for DNA analysis because of perceptions about the limitations of DNA degradation in older specimens. Despite very few exceptions, most DNA barcoding projects, which aim to obtain sequence data from all species, generally use specimens collected specifically for that purpose, instead of the wealth of identified material in museums, constrained by the lack of suitable PCR methods. Any techniques that extend the utility of museum specimens for DNA analysis therefore are highly valuable. This study first tested the effects of specimen age and PCR amplicon size on PCR success rates in pinned insect specimens, then developed a PCR primer set and amplification strategy allowing greatly increased utilization of older museum specimens for DNA barcoding. PCR success rates compare favourably with the few published studies utilizing similar aged specimens, and this new strategy has the advantage of being easily automated for high-throughput laboratory workflows. The strategy uses hemi-nested, degenerate, M13-tailed PCR primers to amplify two overlapping amplicons, using two PCRs per amplicon (i.e. four PCRs per DNA sample). Initial PCR products are reamplified using an internal primer and a M13 primer. Together the two PCR amplicons yield 559 bp of the COI gene from Coleoptera, Lepidoptera, Diptera, Hemiptera, Odonata and presumably also other insects. BARCODE standard-compliant data were recovered from 67% (56 of 84) of specimens up to 25 years old, and 51% (102 of 197) of specimens up to 55 years old. Given the time, cost and specialist expertise required for fieldwork and identification, 'collecting in collections' is a viable alternative allowing researchers to capitalize on the knowledge captured by curation work in decades past.
Data from: Genotyping HapSTR loci: phase determination from direct sequencing of PCR products
HapSTRs combine information from a microsatellite (or simple tandem repeat, STR) with one or more single nucleotide polymorphisms (SNPs) in the DNA sequence immediately flanking the STR. These loci may offer increased power for the estimation of demographic parameters, but also present some challenges for data collection and analysis. We describe a process for inferring HapSTR alleles, including the flanking haplotypes, STR alleles, and their phase relative to each other, directly from DNA sequence electropherograms of PCR products from heterozygous individuals. Our approach eliminates the need for more costly and time-consuming processes such as cloning or acrylamide gel electrophoresis to separate alleles prior to sequencing.
Data from: Molecular profiling of diatom assemblages in tropical lake sediments using taxon-specific PCR and Denaturing High-Performance Liquid Chromatography (PCR-DHPLC)
Here we present a protocol to genetically detect diatoms in sediments of the Kenyan tropical Lake Naivasha, based on taxon-specific PCR amplification of short fragments (approx. 100 bp) of the small subunit ribosomal (SSU) gene and subsequent separation of species-specific PCR products by PCR-based DHPLC. An evaluation of amplicons differing in primer specificity to diatoms and length of the fragments amplified demonstrated that the number of different diatom sequence types detected after cloning of the PCR products critically depended on the specificity of the primers to diatoms and the length of the amplified fragments whereby shorter fragments yielded more species of diatoms. The DHPLC was able to discriminate between very short amplicons based on the sequence difference, even if the fragments were of identical length. and if the amplicons differed only in a small number of nucleotides. Generally the method identified the dominant sequence types from mixed amplifications. A comparison with microscopic analysis of the sediment samples revealed that the sequence types identified in the molecular assessment corresponded well with the most dominant species. In summary, the PCR-based DHPLC protocol offers a fast, reliable, and cost-efficient possibility to study DNA from sediments and other environmental samples with unknown organismic content, even for very short DNA fragments.
Data from: Development of nuclear microsatellite loci and mitochondrial single nucleotide polymorphisms for the natterjack toad, Bufo (Epidalea) calamita (Bufonidae), using next generation sequencing and Competitive Allele Specific PCR (KASPar)
Amphibians are undergoing a major decline worldwide and the steady increase in the number of threatened species in this particular taxa highlights the need for conservation genetics studies using high-quality molecular markers. The natterjack toad, Bufo (Epidalea) calamita, is a vulnerable pioneering species confined to specialized habitats in Western Europe. To provide efficient and cost-effective genetic resources for conservation biologists, we developed and characterized 22 new nuclear microsatellite markers using next-generation sequencing. We also used sequence data acquired from Sanger sequencing to develop the first mitochondrial markers for KASPar assay genotyping. Genetic polymorphism was then analyzed for 95 toads sampled from 5 populations in France. For polymorphic microsatellite loci, number of alleles and expected heterozygosity ranged from 2 to 14 and from 0.035 to 0.720, respectively. No significant departures from panmixia were observed (mean multilocus F IS = −0.015) and population differentiation was substantial (mean multilocus F ST = 0.222, P < 0.001). From a set of 18 mitochondrial SNPs located in the 16S and D-loop region, we further developed a fast and cost-effective SNP genotyping method based on competitive allele-specific PCR amplification (KASPar). The combination of allelic states for these mitochondrial DNA SNP markers yielded 10 different haplotypes, ranging from 2 to 5 within populations. Populations were highly differentiated (G ST = 0.407, P < 0.001). These new genetic resources will facilitate future parentage, population genetics and phylogeographical studies and will be useful for both evolutionary and conservation concerns, especially for the set-up of management strategies and the definition of distinct evolutionary significant units.
Data from: Environmental metabarcodes for insects: in silico PCR reveals potential for taxonomic bias
Studies of insect assemblages are suited to the simultaneous DNA-based identification of multiple taxa known as metabarcoding. To obtain accurate estimates of diversity, metabarcoding markers ideally possess appropriate taxonomic coverage to avoid PCR-amplification bias, as well as sufficient sequence divergence to resolve species. We used in silico PCR to compare the taxonomic coverage and resolution of newly designed insect metabarcodes (targeting 16S) with that of existing markers (16S and COI) and then compared their efficiency in vitro. Existing metabarcoding primers amplified in silico less than 75% of insect species with complete mitochondrial genomes available, whereas new primers targeting 16S provided greater than 90% coverage. Furthermore, metabarcodes targeting COI appeared to introduce taxonomic PCR-amplification bias, typically amplifying a greater percentage of Lepidoptera and Diptera species, while failing to amplify certain orders in silico. To test whether bias predicted in silico was observed in vitro, we created an artificial DNA blend containing equal amounts of DNA from 14 species, representing 11 different insect orders and one arachnid. We PCR-amplified the blend using five primers sets, targeting either COI or 16S, with high-throughput amplicon sequencing yielding more than 6 million reads. In vitro results typically corresponded to in silico PCR predictions, with newly designed 16S primers detecting 11 insect taxa present, thus providing equivalent or better taxonomic coverage than COI metabarcodes. Our results demonstrate that in silico PCR is a useful tool for predicting taxonomic bias in mixed template PCR, and that researchers should be wary of potential bias when selecting metabarcoding markers.
Data from: Attack of the PCR clones: rates of clonality have little effect on RAD-seq genotype calls
Interpretation of high-throughput sequence data requires an understanding of how decisions made during bioinformatic data processing can influence results. One source of bias that is often cited is PCR clones (or PCR duplicates). PCR clones are common in restriction site associated sequencing (RAD-seq) datasets, which are increasingly being used for molecular ecology. To determine the influence PCR clones and the bioinformatic handling of clones have on genotyping, we evaluate four RAD-seq datasets. Datasets were compared before and after clones were removed to estimate the number of clones present in RAD-seq data, quantify how often the presence of clones in a dataset cause genotype calls to change compared to when clones were removed, investigate the mechanisms that lead to genotype call changes, and test if clones bias heterozygosity estimates. Our RAD-seq datasets contained 30 – 60% PCR clones, but 95% of RAD-tags had five or fewer clones. Relatively few genotypes changed once clones were removed (5-10%), and the vast majority of these changes (98%) were associated with genotypes switching from a called to no-call state or vice versa. PCR clones had a larger influence on genotype calls in individuals with low read depth but appeared to influence genotype calls at all loci similarly. Removal of PCR clones reduced the number of called genotypes by 2% but had almost no influence on estimates of heterozygosity. As such, while steps should be taken to limit PCR clones during library preparation, PCR clones are likely not a substantial source of bias for most RAD-seq studies.
Data from: Improving PCR detection of prey in molecular diet studies: importance of group-specific primer set selection and extraction protocol performances
While morphological identification of prey remains in feces of predators is the method most commonly used to study trophic interactions, many studies indicate that this method does not detect all consumed prey. Polymerase Chain Reaction based methods are increasingly used to detect prey DNA in the predator food bolus and have proved themselves efficient, with high accuracy. When studying complex diet samples, the extraction of total DNA is a critical step, as PCR inhibitors may be co-extracted. Another critical step consist in carefully select suitable group-specific primer sets that should only amplify prey DNA from the targeted taxon. In this study, the food boluses of five Rattus rattus and seven Rattus exulans were analyzed using both morphological and molecular methods. We tested a panel of 30 PCR specific primer sets targeting Bird, Invertebrate and Plant sequences and four were finally selected to be use as group-specific primer pairs in PCR protocols. The performances of four DNA extraction protocols (QIAamp DNA stool mini kit, DNeasy mericon food kit and two CTAB-based methods) were compared using four variables: DNA concentration, A260/A280 absorbance ratio, food compartment analyzed (stomach or fecal contents), total number of prey specific PCR amplification per sample. Our results clearly indicate that the A260/A280 absorbance ratio, which varies between extraction protocols, is positively correlated to the number of PCR amplifications of each prey taxon. We recommend using the DNeasy mericon food kit (Qiagen), which yielded results very similar to those achieved with the morphological approach.
Data from: Multiplex preamplification PCR and microsatellite validation allows accurate single nucleotide polymorphism (SNP) genotyping of historical fish scales
Incorporating historical tissues into the study of ecological, conservation, and management questions can broaden the scope of population genetic research by enhancing our understanding of evolutionary processes and anthropogenic influences on natural populations. Genotyping historical and low-quality samples has been plagued by challenges associated with low amounts of template DNA and the potential for preexisting DNA contamination among samples. We describe a two-step process designed to (i) accurately genotype large numbers of historical low-quality scale samples in a high-throughput format and (ii) screen samples for preexisting DNA contamination. First, we describe how an efficient multiplex preamplification PCR of 45 single nucleotide polymorphisms (SNPs) can generate highly accurate genotypes with low failure and error rates in subsequent SNP genotyping reactions of individual historical scales from sockeye salmon (Oncorhynchus nerka). Second, we demonstrate how the method can be modified for the amplification of microsatellite loci to detect preexisting DNA contamination. A total of 760 individual historical scale and 182 contemporary fin clip samples were genotyped and screened for contamination. Genotyping failure and error rates were exceedingly low and similar for both historical and contemporary samples. Preexisting contamination in 21% of the historical samples was successfully identified by screening the amplified microsatellite loci. The potential for automation, low failure and error rates, and ability to multiplex both the preamplification and subsequent genotyping reactions combine to make the protocol ideally suited for efficiently genotyping large numbers of potentially contaminated low-quality sources of DNA.
FIGURE 4 in Description of a new Fridericia species (Oligochaeta: Enchytraeidae) and its molecular comparison with two morphologically similar species by PCRRFLP
FIGURE 4. Fridericia crassiductata sp.n. Fridericia crassiductata sp.n. A = praeclitellar segments (½ X – ½ XII) (sperm funnels marked with arrows, B = Photograph of bursal slits (marked with arrows) of the male copulatory organs, C = Photograph of the subneural gland in XIV (marked with arrow).
FIGURE 3 in Description of a new Fridericia species (Oligochaeta: Enchytraeidae) and its molecular comparison with two morphologically similar species by PCRRFLP
FIGURE 3. Fridericia crassiductata sp.n. Fridericia crassiductata sp.n. Photograph of the clitellar glands (dorsal view).
ScienceDex guides
Understand access before you commit
These curated guides explain access requirements, typical timelines, costs, and reuse considerations for widely used research datasets.
Allen Brain Atlas
Allen Brain Atlas is an Allen Institute collection of brain map atlases, datasets, APIs, and analysis tools covering mouse, human, and non-human primate brain resources.
Annotated Behaviour and Observability Dataset (ABODe)
ABODe is a University of Edinburgh DataShare dataset for behavior classification in group-housed mice using home-cage video, identities, bounding boxes, ground-plate positions, and annotator labels.
DANDI Archive for NWB datasets
DANDI is a BRAIN Initiative archive for publishing and sharing neurophysiology data, including electrophysiology, optophysiology, and behavioral data packaged as NWB and related standards.
International Brain Laboratory public data
The International Brain Laboratory public data releases expose standardized mouse decision-making experiments, including Neuropixels recordings, widefield calcium imaging, behavior, and session metadata accessed through the ONE API.
OpenNeuro
OpenNeuro is a free, open platform for sharing neuroimaging datasets, with public search, dataset pages, and download paths for web, S3, DataLad, and the OpenNeuro CLI.