Pooled DNA Research Articles

Optimizing a metabarcoding marker portfolio for species detection from complex mixtures of globally diverse fishes

AbstractDNA metabarcoding is used to enumerate and identify taxa in both environmental samples and tissue mixtures, but the effectiveness of particular markers depends on their sensitivity to the taxa involved. Using multiple primer sets that amplify different genes can mitigate biases in amplification efficiency, sequence resolution, and reference data availability, but few empirical studies have evaluated markers for complementary performance. Here, we assess the individual and joint performance of 22 markers for detecting species in a DNA pool of 98 species of marine and freshwater bony fishes from geographically and phylogenetically diverse origins. We find that a portfolio of four markers targeting 12S, 16S, and two regions of COI identifies 100% of reference taxa to family and nearly 60% to species. We then use these four markers to evaluate metabarcoding of heterogeneous tissue mixtures, using experimental fishmeal to test: (1) the tissue input threshold to ensure detection; (2) how read depth scales with tissue abundance; and (3) the effect of non‐target material in the mixture on recovery of target taxa. We consistently detect taxa that makeup >1% of fishmeal mixtures and can detect taxa at the lowest input level of 0.01%, but rare taxa (<1%) were detected inconsistently across markers and replicates. Read counts showed only a weak correlation with tissue input, suggesting they are not a reliable quantitative proxy for relative abundance. Despite the limitations arising from primer specificity and reference data availability, our results demonstrate that a modest portfolio of markers can perform well in detecting and identifying aquatic species in complex mixtures despite heterogeneity in tissue representation, phylogenetic affinities, and from a broad geographic range.

Mapping of the Waxy Gene in Brassica napus L. via Bulked Segregant Analysis (BSA) and Whole-Genome Resequencing

Plant cuticular wax is the covering of the outer layer of the plant. It forms a protective barrier on the epidermis of plants and plays a vital role like a safeguard from abiotic and biotic stresses. In the present study, Brassica napus L. materials with and without wax powder were observed. Genetic analysis showed that the separation ratio of waxy plants to waxless plants was 15:1 in the F2 population, which indicated that the wax powder formation was controlled by two pairs of genes. In order to identify the candidate genes associated with the wax powder trait of B. napus L., bulked segregant analysis (BSA) was performed. The homozygous waxy plants, the homozygous waxless plants, and plants from three parents were selected for establishing five DNA pools for genome-wide resequencing. The results of the resequencing showed that the site associated with wax powder trait was located in the region of 590,663–1,657,546 bp on chromosome A08. And 48 single nucleotide polymorphisms (SNPs) were found between the DNA sequences of waxy plants and waxless plants in this region. These SNPs were distributed across 16 gene loci. qRT-PCR analysis was conducted for the 16 candidate genes and three genes (BnaA08g01070D, BnaA08g02130D, and BnaA08g00890D) showed significantly differential expression between waxy and waxless parents. BnaA08g01070D and BnaA08g02130D were significantly down-regulated in the waxless parent, while BnaA08g00890D was significantly up-regulated in the waxless parent. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses revealed that the BnaA08g02130D gene was enriched in lipid biosynthetic or metabolic processes. All the results in our study would provide valuable clues for exploring the genes involved in wax powder development.

Processing DNA Storage through Programmable Assembly in a Droplet-Based Fluidics System.

DNA can be used to store digital data, and synthetic short-sequence DNA pools are developed to store high quantities of digital data. However, synthetic DNA data cannot be actively processed in DNA pools. An active DNA data editing process is developed using splint ligation in a droplet-controlled fluidics (DCF) system. DNA fragments of discrete sizes (100-500bps) are synthesized for droplet assembly, and programmed sequence information exchange occurred. The encoded DNA sequences are processed in series and parallel to synthesize the determined DNA pools, enabling random access using polymerase chain reaction amplification. The sequencing results of the assembled DNA data pools can be orderly aligned for decoding and have high fidelity through address primer scanning. Furthermore, eight 90bps DNA pools with pixel information (png: 0.27-0.28kB), encoded by codons, are synthesized to create eight 270bps DNA pools with an animation movie chip file (mp4: 12kB) in the DCF system.

Saturation genome editing of 11 codons and exon 13 of BRCA2 coupled with chemotherapeutic drug response accurately determines pathogenicity of variants.

The unknown pathogenicity of a significant number of variants found in cancer-related genes is attributed to limited epidemiological data, resulting in their classification as variant of uncertain significance (VUS). To date, Breast Cancer gene-2 (BRCA2) has the highest number of VUSs, which has necessitated the development of several robust functional assays to determine their functional significance. Here we report the use of a humanized-mouse embryonic stem cell (mESC) line expressing a single copy of the human BRCA2 for a CRISPR-Cas9-based high-throughput functional assay. As a proof-of-principle, we have saturated 11 codons encoded by BRCA2 exons 3, 18, 19 and all possible single-nucleotide variants in exon 13 and multiplexed these variants for their functional categorization. Specifically, we used a pool of 180-mer single-stranded donor DNA to generate all possible combination of variants. Using a high throughput sequencing-based approach, we show a significant drop in the frequency of non-functional variants, whereas functional variants are enriched in the pool of the cells. We further demonstrate the response of these variants to the DNA-damaging agents, cisplatin and olaparib, allowing us to use cellular survival and drug response as parameters for variant classification. Using this approach, we have categorized 599 BRCA2 variants including 93-single nucleotide variants (SNVs) across the 11 codons, of which 28 are reported in ClinVar. We also functionally categorized 252 SNVs from exon 13 into 188 functional and 60 non-functional variants, demonstrating that saturation genome editing (SGE) coupled with drug sensitivity assays can enhance functional annotation of BRCA2 VUS.

An RNA‐Cleaving DNAzyme That Requires an Organic Solvent to Function

AbstractEngineering functional nucleic acids that are active under unusual conditions will not only reveal their hidden abilities but also lay the groundwork for pursuing them for unique applications. Although many DNAzymes have been derived to catalyze diverse chemical reactions in aqueous solutions, no prior study has been set up to purposely derive DNAzymes that require an organic solvent to function. Herein, we utilized in vitro selection to isolate RNA‐cleaving DNAzymes from a random‐sequence DNA pool that were “compelled” to accept 35 % dimethyl sulfoxide (DMSO) as a cosolvent, via counter selection in a purely aqueous solution followed by positive selection in the same solution containing 35 % DMSO. This experiment led to the discovery of a new DNAzyme that requires 35 % DMSO for its catalytic activity and exhibits drastically reduced activity without DMSO. This DNAzyme also requires divalent metal ions for catalysis, and its activity is enhanced by monovalent ions. A minimized, more efficient DNAzyme was also derived. This work demonstrates that highly functional, organic solvent‐dependent DNAzymes can be isolated from random‐sequence DNA libraries via forced in vitro selection, thus expanding the capability and potential utility of catalytic DNA.

An RNA-Cleaving DNAzyme That Requires an Organic Solvent to Function.

Engineering functional nucleic acids active under unusual conditions will not only reveal the hidden talents of nucleic acids but also lay groundwork for pursuing them for unique applications. Although many DNAzymes have been derived to catalyze diverse chemical reactions in aqueous solutions, no prior study has been set up to purposely derive DNAzymes that require an organic solvent to function. Herein, we utilized in vitro selection to isolate RNA-cleaving DNAzymes from a random-sequence DNA pool that were "compelled" to accept 35% dimethyl sulfoxide (DMSO) as a cosolvent, via counter selection in a purely aqueous solution followed by positive selection in the same solution containing 35% DMSO. This experiment indeed led to the discovery of a new DNAzyme that requires 35% DMSO for its catalytic activity but exhibits drastically reduced activity without DMSO. This DNAzyme also requires divalent metal ions for catalysis and uses monovalent ions for activity enhancement. A minimized, more efficient DNAzyme was also derived. This work demonstrates that highly functional organic solvent-dependent DNAzymes can be isolated from random-sequence DNA libraries via forced in vitro selection, thus expanding the capability and potential utility of DNA as enzymes.

In Vitro Selection of M2+-Independent, Fast-Responding Acidic Deoxyribozymes for Bacterial Detection.

We report on the first efforts to isolate acidic RNA-cleaving DNAzymes (aRCDs) from a random-sequence DNA pool by in vitro selection that are activated by a microbe Escherichia coli (E. coli), at pH 5.3. Importantly, these E. coli-responsive aRCDs only require monovalent metal ions as cofactors for cleaving a fluorogenic chimeric DNA/RNA substrate. Such characteristics can be used to efficiently protect RCDs from both intrinsic chemical instability and external enzymatic degradation. One remarkable DNAzyme, aRCD-EC1, is specific for E. coli, and its target is likely a protein. Furthermore, truncated aRCD-EC1 had significantly improved catalytic activity with an observed rate constant (kobs) of 1.18 min-1, making it the fastest bacteria-responding RCD reported to date. Clinical evaluation of this aRCD-based fluorescent assay using 40 patient urine samples demonstrated a diagnostic sensitivity of 100% and a specificity of 100% at a total analysis time of 50 min without a bacterial culture. This work can expand the repertoire of DNAzymes that are active under nonphysiological conditions, thus facilitating the development of diverse DNAzyme-based biosensors in clinical diagnosis.

A multiplexed plant-animal SNP array for selective breeding and species conservation applications.

Reliable and high-throughput genotyping platforms are of immense importance for identifying and dissecting genomic regions controlling important phenotypes, supporting selection processes in breeding programs, and managing wild populations and germplasm collections. Amongst available genotyping tools, single nucleotide polymorphism arrays have been shown to be comparatively easy to use and generate highly accurate genotypic data. Single-species arrays are the most commonly used type so far; however, some multi-species arrays have been developed for closely related species that share single nucleotide polymorphism markers, exploiting inter-species cross-amplification. In this study, the suitability of a multiplexed plant-animal single nucleotide polymorphism array, including both closely and distantly related species, was explored. The performance of the single nucleotide polymorphism array across species for diverse applications, ranging from intra-species diversity assessments to parentage analysis, was assessed. Moreover, the value of genotyping pooled DNA of distantly related species on the single nucleotide polymorphism array as a technique to further reduce costs was evaluated. Single nucleotide polymorphism performance was generally high, and species-specific single nucleotide polymorphisms proved suitable for diverse applications. The multi-species single nucleotide polymorphism array approach reported here could be transferred to other species to achieve cost savings resulting from the increased throughput when several projects use the same array, and the pooling technique adds another highly promising advancement to additionally decrease genotyping costs by half.

Opportunities and inherent limits of using environmental DNA for population genetics

AbstractMolecular techniques using DNA retrieved from community or environmental samples, in particular environmental DNA (eDNA), are becoming increasingly popular for detecting individual species, assessing biodiversity, and quantifying ecological indices. More recently, eDNA has also been proposed as a template for population genetics, and several studies have already tested the feasibility of this approach, mostly looking at vertebrate species. Their results along with general opportunities offered by these types of “community‐based” samples, such as the possibility to target multiple species at the same time, have generated great enthusiasm and expectations for using eDNA in population genetics. However, not every aspect of population genetics can be addressed by eDNA‐based data and some inherent limitations may challenge its conclusions. Here, we firstly review the state of current knowledge of DNA retrieved from environmental and community samples for population genetics. Then, focusing on eDNA, we summarize the opportunities but also detail four main limitations of its use for population‐level inferences, namely, (1) the difficulty to retrieve a species‐specific dataset, (2) the potential lack of correlation between observed and true allelic frequencies, (3) the loss of individual information in multi‐locus genotyping and linkage between loci, and (4) the uncertainty about the individuals contributing to the sampled DNA pool (e.g., number, life‐stage, or sex). Some of these limitations might be overcome with the development of new technologies or models that account for the specificities of eDNA. Others, however, are inherent, and their effect on the inferences must be thoroughly evaluated. The possibility of gaining insights into genetic diversity and population structure from DNA retrieved from community and environmental samples is appealing for scientists, conservation managers, and other practitioners. Yet, to avoid false expectations and incorrect inferences, it is imperative that these limitations are known and considered alongside the opportunities and advantages.

Identification genetic variations in some heat shock protein genes of Tali goat breed and study their structural and functional effects on relevant proteins.

Animals of different regions have adapted to adverse environmental conditions by modifying their phenotypic and genotypic characteristics in the long run. In this study, the effect of genetic variations of 10 heat shock protein (HSP) genes (HSP70A4, HSP70A9, HSP40C17, HSP40C27, HSP90AA1, HSP90AB1, HSPB7, HSPB11, HSPD1 and HSPE1) on the three-dimensional protein structure and function of proteins in Tali goat (a tropical breed) were studied and were compared with Saanen goat (as a sensitive breed). A pooled DNA of 15 samples from blood was sequenced and mapped to the goat reference sequence. The bioinformatics analysis was used to identify nsSNPs in the Tali breed and was compared with the Saanen goat. Four online bioinformatics tools (Sorting Intolerant from Tolerant, Protein Variation Effect Analyzer, Polymorphism Phenotyping version2 and Single Nucleotide Polymorphism Database and Gene Ontology) showed three deleterious missense nsSNPs and seven natural missense SNPs in these HSPs genes of Tali goat. Out of 10 reported nsSNPs, 5 nsSNPs in HSP70A4, 1 nsSNP inHSP70A9, 2 nsSNPs in HSP40C17, 1 nsSNP in HSP40C27 and 1 nsSNP in HSPD1 were detected. ConSurf tools showed that the majority of the predicted nsSNPs occur in conserved sites. Moreover, several post-translational modification (PTM) predictors computed the probability of post-translation change of nsSNPs. The putative phosphorylation and glycosylation sites in HSPs proteins were substitutions rs669769139 and rs666336692 of the Tali goat breed. These results on the effect of type of genetic variants on the function of HSP proteins will assist to predict the resistance to hard conditions in goat breeds. Considering that the identified SNPid rs669769139 (S248) which is located on the N-terminal ATPase domain of HSP70A4 is a PTM site with a highly conserved score and a natural substitution on changing the stability and benign protein that can affect the functional and structural characterization of HSPs protein for adaptation to the local climate.

Tick populations and molecular detection of selected tick-borne pathogens in questing ticks from northern and central Tanzania.

Ticks are vectors and reservoirs of a variety of pathogens including protozoa, bacteria and viruses which cause tick-borne diseases (TBDs) in humans and livestock. TBDs pose serious constraints to the improvement of livestock production in tropical and subtropical regions of the world. Despite their wide distribution, information on the tick and pathogen relationship is scarce in Tanzania. We used nested PCR and sequencing to screen pathogens of public and veterinary health importance in ticks collected by flagging from four districts of Tanzania. In total, 2021 ticks comprising nine species were identified. DNA from ticks was pooled according to tick species, developmental stage, and location, then screened for Babesia bigemina, Babesia bovis, Theileria parva and Coxiella burnetii. Out of 377 pools, 34.7% were positive for at least one pathogen. Theileria parva was the most abundant with a minimum infection rate (MIR) of 2.8%, followed by B. bigemina (MIR = 1.8%) and B. bovis (MIR = 0.8%). Multiple pathogens detection was observed in 7.2% of the tested pools. However, PCR screening of individual tick DNA revealed that only 0.3% of the examined pools had co-infection. DNA of C. burnetii was never detected in any tick DNA pool. The MIR of tick-borne pathogens (TBPs) differed significantly among districts, seasons, tick species, and tick developmental stages. Sequence analysis showed that B. bigemina RAP-1a, B. bovis SBP-4, and T. parva p104 genes were conserved among pathogens in the four districts. Despite the absence of C. burnetii in ticks, considering its pathogenic potential, it is essential to continue monitoring for its possible recurrence in ticks. This information adds to the knowledge of TBPs epidemiology and will contribute to the scientific basis for planning future control strategies.

Features of bacterial DNA taxonomy in blood of patients with various metabolic phenotypes of obesity

Aim. To study the blood microbiome taxonomy in patients with metabolically healthy obesity (MHO) and metabolically unhealthy obesity (MUHO).Materials and methods. The study included healthy donors without obesity (n = 116) and obese patients who were divided into subgroups with MHO (n = 36) and MUHO (n = 53). Bacterial DNA isolated from blood samples was subject to metagenomic sequencing of the v3–v4 variable region in the 16S rRNA gene. We compared the frequency of isolating certain taxa from the samples and the proportion of these taxa in the total pool of bacterial DNA in the blood.Results. MUHO patients showed an increase in Lachnospiraceae, Ruminococcaceae, and Prevotellaceae, which are the main taxa in gut microbiota. This may indicate greater intestinal permeability in such patients. Obese patients, regardless of the metabolic phenotype of obesity, more often had Rhodobacteraceae, Streptomycetaceae, Leuconostocaceae, and Burkholderiaceae DNA in their blood. Nocardioidaceae, Flavobacteriaceae, Hyphomicrobiaceae, and Gaiellaceae DNA were more frequently present in the blood microbiome of patients with MHO, whereas MUHO patients more often had S24-7, Nocardiaceae, and Helicobacteraceae DNA in their blood. Many members of these families inhabit soil and water, which may indicate increased skin barrier permeability in obese patients. Additionally, a higher number of Helicobacteraceae-positive blood samples in the MUHO patient group may indicate increased translocation from the stomach.Conclusion. Obesity is accompanied by changes in the taxonomic composition of the blood microbiome. Moreover, the nature of the changes depends on the metabolic phenotype of obesity and the permeability of external barriers.

Vibrio-Sequins - dPCR-traceable DNA standards for quantitative genomics of Vibrio spp

BackgroundVibrio spp. are a diverse group of ecologically important marine bacteria responsible for several foodborne outbreaks of gastroenteritis around the world. Their detection and characterization are moving away from conventional culture-based methods towards next generation sequencing (NGS)-based approaches. However, genomic methods are relative in nature and suffer from technical biases arising from library preparation and sequencing. Here, we introduce a quantitative NGS-based method that enables the quantitation of Vibrio spp. at the limit of quantification (LOQ) through artificial DNA standards and their absolute quantification via digital PCR (dPCR).ResultsWe developed six DNA standards, called Vibrio-Sequins, together with optimized TaqMan assays for their quantification in individually sequenced DNA libraries via dPCR. To enable Vibrio-Sequin quantification, we validated three duplex dPCR methods to quantify the six targets. LOQs were ranging from 20 to 120 cp/µl for the six standards, whereas the limit of detection (LOD) was ~ 10 cp/µl for all six assays. Subsequently, a quantitative genomics approach was applied to quantify Vibrio-DNA in a pooled DNA mixture derived from several Vibrio species in a proof-of-concept study, demonstrating the increased power of our quantitative genomic pipeline through the coupling of NGS and dPCR.ConclusionsWe significantly advance existing quantitative (meta)genomic methods by ensuring metrological traceability of NGS-based DNA quantification. Our method represents a useful tool for future metagenomic studies aiming at quantifying microbial DNA in an absolute manner. The inclusion of dPCR into sequencing-based methods supports the development of statistical approaches for the estimation of measurement uncertainties (MU) for NGS, which is still in its infancy.

Long-term warming of a forest soil reduces microbial biomass and its carbon and nitrogen use efficiencies

Global warming impacts biogeochemical cycles in terrestrial ecosystems, but it is still unclear how the simultaneous cycling of carbon (C) and nitrogen (N) in soils could be affected in the longer-term. Here, we evaluated how 14 years of soil warming (+4 °C) affected the soil C and N cycle across different soil depths and seasons in a temperate mountain forest. We used H218O incorporation into DNA and 15N isotope pool dilution techniques to determine gross rates of C and N transformation processes. Our data showed different warming effects on soil C and N cycling, and these were consistent across soil depths and seasons. Warming decreased microbial biomass C (−22%), but at the same time increased microbial biomass-specific growth (+25%) and respiration (+39%), the potential activity of β-glucosidase (+31%), and microbial turnover (+14%). Warming reduced gross rates of protein depolymerization (−19%), but stimulated gross N mineralization (+63%) and the potential activities of N-acetylglucosaminidase (+106%) and leucine-aminopeptidase (+46%), and had no impact on gross nitrification (+1%). Microbial C and N use efficiencies were both lower in the warming treatment (−15% and −17%, respectively). Overall, our results suggest that long-term warming drives soil microbes to incorporate less C and N into their biomass (and necromass), and to release more inorganic C and N to the environment, causing lower soil C and N storage in this forest, as indicated by lower soil C and total N contents. The decreases in microbial CUE and NUE were likely triggered by increasing microbial P constraints in warmed soils, limiting anabolic processes and microbial growth and promoting pervasive losses of C and N from the soil.

Molecular detection of Fasciola, Schistosoma and Paramphistomum species from freshwater snails occurring in Gauteng and Free State provinces, South Africa

Trematodiases are diseases caused by snail-borne trematode parasites that infect both animals and humans. Fascioliasis, schistosomiasis and paramphistomosis are some of these diseases and they affect millions of livestock, leading to significant economic losses. The aim of the study was to document freshwater snails occurring in selected study sites in the Free State and Gauteng provinces as well as identify and detect larval trematodes that they harbour. Samples were collected from a total of five study sites within two provinces of South Africa. Morphological features were used to identify snail species and were further confirmed genetically by polymerase chain reaction (PCR), sequencing and phylogenetic analysis. The larval trematodes were also detected by PCR, PCR-Restriction Length Fragment Polymorphism (PCR-RLFP), sequencing and phylogenetic analysis. A total of 887 freshwater snails were collected from Free State (n = 343) and Gauteng (n = 544). Five different genera of snails as well as species in the Succineidae family were documented. The snails in descending order of abundance were identified as: Physa (P.) spp. (51%), Succineidae spp. (20%), Galba (G.) truncatula (12%), Pseudosuccinea (Ps.) columella (10%), Planorbella (Pl.) duryi (6%) and Bulinus (B.) truncatus (1%). Approximately 272 DNA pools were created for genetic identification of snails and detection of trematode parasites. Schistosoma species were not detected from any of the snail species. A total prevalence of 46% was obtained for Fasciola hepatica in the identified snail species across all study sites. Overall, the highest prevalence of F. hepatica was obtained in Physa species (24%), whilst the lowest was observed in B. truncatus snails (1%). Forty three percent (43%) of the snail samples were PCR positive for Paramphistomum DNA. This is the first report of P. mexicana in South Africa. Fasciola hepatica was confirmed from all obtained snail species per study site. This is the first reported detection of F. hepatica in Pl. duryi and P. mexicana snails as well as the first confirmation of natural infection from P. acuta in South Africa.

Sustainable DNA Data Storage on Cellulose Paper.

DNA is a promising material for high density and long-term archival data storage. In addition to algorithms for encoding digital information into DNA sequences, the DNA writing (chemical synthesis) and reading (DNA sequencing), the preservation of DNA mixtures with high sequence diversity is another critical issue for sustainable, long-term, and large-scale DNA data storage. Here, this work demonstrates a method for low-cost, convenient and sustainable DNA data storage on cellulose paper. A DNA pool comprising thousands of sequences, in which archival data are encoded, is conveniently stored on a cellulose paper with a calculated density as high as 15TB per mm3 through electrostatic adsorption. This work demonstrates that these digitally encoded DNA pools can be stable for years on the cellulose paper after drying even when directly exposed to air. Furthermore, the reversible electrostatic adsorption enables repeated loading/retrieval of DNA on/off cellulose paper. Therefore, this sustainable DNA preservation on cellulose paper through the convenient electrostatic adsorption exhibits a great advantage in terms of storage capacity and cost that is crucial for practical systems to achieve large-scale and long-time data storage.

MFAST-SeqS based aneuploidy score in circulating cell-free DNA and role as early response marker in patients with metastatic prostate cancer treated with androgen receptor signaling inhibitor.

5058 Background: Several treatment modalities in metastatic castration resistant prostate cancer (mCRPC) are available to prolong progression-free and overall survival. With the arrival of additional treatment modalities, the need for accurate monitoring of treatment response is becoming more eminent and research for biomarkers pivotal. Cell-free circulating tumor DNA (ctDNA) has emerged as a promising prognostic and predictive biomarker. Several techniques have been employed for the detection and characterization of ctDNA within the total pool of cell-free DNA (cfDNA), one of which is the modified Fast Aneuploidy Screening Test-Sequencing System (mFAST-SeqS). This affordable and robust assay enables the quantitation of a sample’s ctDNA using a genome-wide aneuploidy score (GWA). Our aim was to investigate whether estimation of the GWA by mFAST-SeqS can be used to evaluate early response to treatment and predict response to treatment at baseline in patients with mCRPC. Methods: We prospectively enrolled mCRPC patients before start of treatment with androgen receptor signaling inhibitor (ARSI) abiraterone or enzalutamide. Blood samples were collected at baseline before start of treatment (BL, n= 134) and at an early treatment time point during treatment (ET, n= 20). We isolated cfDNA from plasma collected at both time points using the QiaSymphony or Maxwell system, and performed mFAST-SeqS on 1 ng cfDNA by amplifying and sequencing long interspaced nuclear elements (LINE-1) throughout the genome. The GWA-scores were calculated by taking the summed square of individual Z scores per chromosome arm relative to healthy controls. GWA-score was dichotomized in high (GWAhigh) and low (GWAlow), based on the previously described cut-off of 5. Clinical outcome, defined as treatment duration with ARSI, was compared for patients with a GWAhigh and GWAlow score at baseline and at an early time point. In addition, conversion of GWA score from baseline to early time point was explored. Results: Median age at start of treatment was 68.5 years (inter-quartile range (IQR): 63-73). Median time between start treatment and blood draw at BL and ET was 3 (IQR: 0-10 days before treatment) and 28 (IQR: 18-62 days during treatment) days, respectively. Median number of prior therapy lines was 1 (IQR: 0-10). Treatment duration was significantly shorter in the GWAhigh group versus the GWAlow group both at BL and at ET in patients treated with ARSI (BL: p<0.001, log-rank test, median 221 and 82 days; ET: p<0.01, log-rank test, median 123 and 42 days). Conclusions: The genome-wide aneuploidy score, based on mFAST-SeqS of cfDNA, is a useful tool to predict response to ARSI in patients with mCRPC. The current dataset will be extended to 199 samples at baseline and 78 samples at early time point, and also include mCRPC patients treated with taxanes. Clinical trial information: NCT01855477 , NTR732 .

Brief restriction endonuclease digestion of genomic DNA improves PCR amplifiability and reproducibility of SSR loci: Augmenting exploration of hidden genetic variability in an endemic carp of South-East Asia

Majority of the microsatellite primers developed through painstaking, resource intensive research often fail to amplify due to secondary structures in the repeat rich target. In the present work, we describe the use of restriction endonuclease digestion of genomic DNA prior to PCR to counter this issue. The methodology, Restriction Endonuclease Digestion of genomic DNA to improve PCR Amplifiability and Repeatability of SSR loci (REDDAR-SSR), was tested on 40 species-specific Simple Sequence Repeat (SSR) loci in Osteobrama belangeri (F: Cyprinidae). Undigested and HpaII digested pooled genomic DNA samples were used as templates. Two primer concentrations (10 pM and 25 pM) and two annealing temperatures (56 °C uniformly and individual primer-specific annealing temperatures) were tested on both template types in sets of three, repeated thrice (360 reactions/condition). The digested templates exhibited significantly higher (P < 0.05) amplifiability (93.9 % against 24.16 % of undigested counterpart) as well as repeatability (94.47 % against 21.56 % of undigested counterpart). Primer concentration had no significant effect on outcomes (P > 0.05). The number of successfully amplified loci in our method was 38 compared to 18 by the conventional protocol. All 38 loci could also be reliably amplified in individual gDNA using the developed protocol out of which 9 loci were observed to be polymorphic. Notably, 4 of the polymorohic loci could be amplified only through REDDAR-SSR. Our protocol can potentially reduce expenses; resources & time vis-a-vis enhance the reach of SSR markers for genotyping species of commercial or conservational significance.

Use of overlapping DNA pools to discern genetic differences despite pooling error.

Genotyping pools of commercial cattle and individual seedstock animals may reveal hidden relationships between sectors enabling use of commercial data for genetic evaluation. However, commercial data capture may be compromised by inexact pool formation. We aimed to estimate the concordance between distances or genomic covariance among pooling allele frequencies (PAFs) of DNA pools comprised of 100 animals with 0% or 50% overlap of animals in common between pools. Cattle lung samples were collected from a commercial beef processing plant on a single day. Six pools of 100 animals each were constructed so that overlap between pools was 0% or 50%. Two pools of all 200 animals were constructed to estimate PAFs for all 200 animals. Frozen lung tissue (0.01 g) from each animal was weighed into a tube containing a pool; there were two pools of 200 animals each and six pools of 100 animals each. Every contribution of an individual animal was an independent measurement to insure independence of pooling errors. Lung samples were kept on dried ice during the pooling process to keep them from thawing. The eight pools were then assayed for approximately 100,000 single nucleotide polymorphisms (SNP). PAF for each SNP and pool was based on the relative intensity of the two dyes used to detect the alleles rather than genotype calls which are not tractable from pooling data. Euclidean distances and genomic relationships among the PAFs for the eight pools were estimated and distances were tested for concordance with pool overlap using permutation-based analysis of distance. Distances among pools were concordant with the planned overlap of animals shared between pools (P = 0.0024); pool overlap accounted for 70% of the variation and pooling error accounted for 30%. Pools containing 100 animals with no overlap were the most distant from one another and pools with 50% overlap were the least distant. This work shows that we can discern differences in distance between pairs of overlapping DNA pools sharing 0% and 50% of the animals. Genomic correlations among nonoverlapping pools indicated that nonoverlapping pool pairs did not share many related animals because genomic correlations were near zero for these pairs. On the other hand, one pair of nonoverlapping pools likely contained related animals between pools because the correlation was 0.21. Pools sharing 50% overlap ranged in genomic relationship between 0.21 and 0.39 (N = 12).

Relic DNA effects on the estimates of bacterial community composition and taxa dynamics in soil

DNA-based analyses have become routine methods in soil microbial research, for their high throughput and resolution in characterizing microbial communities. Yet, concerns arise regarding the interference of relic DNA in estimates of viable bacterial community composition and individual taxa dynamics in soils that recovered from post-gamma irradiation. In this study, different soil samples with varying bacterial diversity but similar soil properties were randomly selected. We split each sample into two parts: one part was treated with propidium monoazide (PMA) before DNA extraction, PMA can bind to relic DNA and inhibit PCR amplification by chemical modification; DNA of the other part was extracted following the same process but without PMA pretreatment. Then, soil bacterial abundance was quantified by quantitative polymerase chain reaction, and bacterial community structure was examined by Illumina metabarcoding sequencing of 16S rRNA gene. The results showed that the higher bacterial richness and evenness were estimated when relic DNA was present. The variation trends of bacterial abundance, alpha diversity, and beta diversity remained the same, as reflected by the significant correlations between PMA-treated and -untreated samples (P < 0.05). Moreover, as the mean abundance increased, the reproducibility of detecting individual taxa dynamics between relic DNA present and absent treatments increased. These findings provide empirical evidence that a more even distribution of species abundance derived from relic DNA would result in the overestimation of richness in the total DNA pools and also have crucial implications for guiding proper application of high-throughput sequencing to estimate bacterial community diversity and taxonomic population dynamic. KEY POINTS: • Relic DNA effects on the bacterial community in sterilized soils were assessed. • More even species abundance distribution in relic DNA overestimates true richness. • The reproducibility of individual taxa dynamics increased with their abundance.