scholarly journals Automated Workflow for Somatic and Germline Next Generation Sequencing Analysis in Routine Clinical Cancer Diagnostics

Cancers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1691
Author(s):  
Muscarella ◽  
Fabrizio ◽  
De Bonis ◽  
Mancini ◽  
Balsamo ◽  
...  

Thanks to personalized medicine trends and collaborations between industry, clinical research groups and regulatory agencies, next generation sequencing (NGS) is turning into a common practice faster than one could have originally expected. When considering clinical applications of NGS in oncology, a rapid workflow for DNA extraction from formalin-fixed paraffin-embedded (FFPE) tissue samples, as well as producing high quality library preparation, can be real challenges. Here we consider these targets and how applying effective automation technology to NGS workflows may help improve yield, timing and quality-control. We firstly evaluated DNA recovery from archived FFPE blocks from three different manual extraction methods and two automated extraction workstations. The workflow was then implemented to somatic (lung/colon panel) and germline (BRCA1/2) library preparation for NGS analysis exploiting two automated workstations. All commercial kits gave good results in terms of DNA yield and quality. On the other hand, the automated workstation workflow has been proven to be a valid automatic extraction system to obtain high quality DNA suitable for NGS analysis (lung/colon Ampli-seq panel). Moreover, it can be efficiently integrated with an open liquid handling platform to provide high-quality libraries from germline DNA with more reproducibility and high coverage for targeted sequences in less time (BRCA1/2). The introduction of automation in routine workflow leads to an improvement of NGS standardization and increased scale up of sample preparations, reducing labor and timing, with optimization of reagents and management.

2020 ◽  
Author(s):  
Buddhini Ranawaka ◽  
Milos Tanurdzic ◽  
Peter Waterhouse ◽  
Fatima Naim

Abstract Background All flowering plants have evolved through multiple rounds of polyploidy throughout the evolutionary process. Intergenomic interactions between subgenomes in polyploid plants are predicted to induce chromatin modifications such as histone modifications to regulate expression of gene homoeologs. Nicotiana benthamiana is an ancient allotetraploid plant with ecotypes collected from climatically diverse regions of Australia. Studying the differences in chromatin landscape of this unique collection will shed light on the importance of chromatin modifications in gene regulation in polyploids as well its implications in adaptation of plants in environmentally diverse conditions. N.benthamiana is also an important biotechnological tool and it is widely used in virological research and functional genomics. Chromatin Immunoprecipitation and high throughput DNA sequencing (ChIP-seq) is well established technique used to study histone modifications. However, due to the starchy nature of mature N.benthamiana leaves, previously published protocols were unsuitable. The aim of this study was to optimise ChIP protocol for N.benthamiana leaves to facilitate comparison of chromatin modifications in two closely related ecotypes. Results Several steps of ChIP were optimised including tissue harvesting, nuclei isolation, nuclei storage, DNA shearing and DNA recovery. The higher amounts of starch in mature N.benthamiana leaves that co-precipitated with nuclei using previously published protocols, hindered chromatin shearing and resulted in low recovery of ChIP DNA. The optimised method reduced starch contamination and resulted in isolation of high quality nuclei suitable for next generation sequencing. Commonly available antibodies targeting histone 3 lysine 4 trimethylation (H3K4me3) and histone 3 lysine 9 dimethylation (H3K9me2) histone modifications were used and success of ChIP was confirmed by PCR and next generation sequencing. Conclusions An optimised ChIP method for mature leaves of N.benthamiana is described. It is relatively less laborious than previously published protocols and allows extraction of high quality nuclear genomic DNA from N.benthamiana. It is also the first comprehensive ChIP method for starchy leaves of N.benthamiana suitable for preparation of ChIP libraries for next generation sequencing.


2019 ◽  
Vol 2 (2) ◽  
pp. 54 ◽  
Author(s):  
Md Masud Rana ◽  
Murat Aycan ◽  
Takeshi Takamatsu ◽  
Kentaro Kaneko ◽  
Toshiaki Mitsui ◽  
...  

Next-generation sequencing (NGS) is a revolutionary advancement allowing large-scale discovery of functional molecular markers that has many applications, including plant breeding. High-quality genomic DNA (gDNA) is a prerequisite for successful NGS library preparation and sequencing; however, few reliable protocols to obtain such plant gDNA exist. A previously reported nuclear pellet (NP) method enables extraction of high-yielding gDNA from fresh leaf tissue of maize (Zea mays L.), but the quality does not meet the stringent requirements of NGS. In this study, we optimized the NP method for whole-genome sequencing of rice (Oryza sativa L.) through the integration of simple purification steps. The optimized NP method relied on initial nucleus enrichment, cell lysis, extraction, and subsequent gDNA purification buffers. The purification steps used proteinase K, RNase A, phenol/chloroform/isoamyl alcohol (25:24:1), and chloroform/isoamyl alcohol (24:1) treatments for protein digestion and RNA, protein, and phenol removal, respectively. Our data suggest that this optimized NP method allowed extraction of consistently high-yielding and high-quality undegraded gDNA without contamination by protein and RNA. Moreover, the extracted gDNA fulfilled the quality metrics of NGS library preparation for the Illumina HiSeq X Ten platform by the TruSeq DNA PCR-Free Library Prep Kit (Illumina). We provide a reliable step-by-step guide to the extraction of high-quality gDNA from fresh leaf tissues of rice for molecular biologists with limited resources.


2016 ◽  
Author(s):  
Melissa Gymrek

Over the past several decades, the forensic and population genetic communities have increasingly leveraged short tandem repeats (STRs) for a variety of applications. The advent of next-generation sequencing technologies and STR-specific bioninformatic tools has enabled the profiling of hundreds of thousands of STRs across the genome. Nonetheless, these genotypes remain error-prone, hindering their utility in downstream analyses. One of the primary drivers of STR genotyping errors are “stutter” artifacts arising during the PCR amplification step of library preparation that add or delete copies of the repeat unit in observed sequencing reads. Recently, Illumina developed the TruSeq PCR-free library preparation protocol which eliminates the PCR step and theoretically should reduce stutter error. Here, I compare two high coverage whole genome sequencing datasets prepared with and without the PCR-free protocol. I find that this protocol reduces the percent of reads due to stutter by more than four-fold and results in higher confidence STR genotypes. Notably, stutter at homopolymers was decreased by more than 6-fold, making these previously inaccessible loci amenable to STR calling. This technological improvement shows good promise for significantly increasing the feasibility of obtaining high quality STR genotypes from next-generation sequencing technologies.


Genes ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1113
Author(s):  
Michael Schwabe ◽  
Sven Griep ◽  
Henrike Schmidtberg ◽  
Rudy Plarre ◽  
Alexander Goesmann ◽  
...  

The clothes moth Tineola bisselliella is one of a few insects that can digest keratin, leading to the destruction of clothing, textiles and artwork. The mechanism of keratin digestion is not yet fully understood, partly reflecting the lack of publicly available genomic and transcriptomic data. Here we present a high-quality gut transcriptome of T. bisselliella generated from larvae reared on keratin-rich and keratin-free diets. The overall transcriptome consists of 428,221 contigs that were functionally annotated and screened for candidate enzymes involved in keratin utilization. As a mechanism for keratin digestion, we identified cysteine synthases, cystathionine β-synthases and cystathionine γ-lyases. These enzymes release hydrogen sulfite, which may reduce the disulfide bonds in keratin. The dataset also included 27 differentially expressed contigs with trypsin domains, among which 20 were associated with keratin feeding. Finally, we identified seven collagenases that were upregulated on the keratin-rich diet. In addition to this enzymatic repertoire potentially involved in breaking down keratin, our analysis of poly(A)-enriched and poly(A)-depleted transcripts suggested that T. bisselliella larvae possess an unstable intestinal microbiome that may nevertheless contribute to keratin digestion.


2021 ◽  
Author(s):  
Michael Schneider ◽  
Asis Shrestha ◽  
Agim Ballvora ◽  
Jens Leon

Abstract BackgroundThe identification of environmentally specific alleles and the observation of evolutional processes is a goal of conservation genomics. By generational changes of allele frequencies in populations, questions regarding effective population size, gene flow, drift, and selection can be addressed. The observation of such effects often is a trade-off of costs and resolution, when a decent sample of genotypes should be genotyped for many loci. Pool genotyping approaches can derive a high resolution and precision in allele frequency estimation, when high coverage sequencing is utilized. Still, pool high coverage pool sequencing of big genomes comes along with high costs.ResultsHere we present a reliable method to estimate a barley population’s allele frequency at low coverage sequencing. Three hundred genotypes were sampled from a barley backcross population to estimate the entire population’s allele frequency. The allele frequency estimation accuracy and yield were compared for three next generation sequencing methods. To reveal accurate allele frequency estimates on a low coverage sequencing level, a haplotyping approach was performed. Low coverage allele frequency of positional connected single polymorphisms were aggregated to a single haplotype allele frequency, resulting in two to 271 times higher depth and increased precision. We compared different haplotyping tactics, showing that gene and chip marker-based haplotypes perform on par or better than simple contig haplotype windows. The comparison of multiple pool samples and the referencing against an individual sequencing approach revealed whole genome pool resequencing having the highest correlation to individual genotyping (up to 0.97), while transcriptomics and genotyping by sequencing indicated higher error rates and lower correlations.ConclusionUsing the proposed method allows to identify the allele frequency of populations with high accuracy at low cost. This is particularly interesting for conservation genomics in species with big genomes, like barley or wheat. Whole genome low coverage resequencing at 10x coverage can deliver a highly accurate estimation of the allele frequency, when a loci-based haplotyping approach is applied. Using annotated haplotypes allows to capitalize from biological background and statistical robustness.


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