scholarly journals Whole-genome sequencing reveals rare off-target mutations in CRISPR/Cas9-edited grapevine

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Xianhang Wang ◽  
Mingxing Tu ◽  
Ya Wang ◽  
Wuchen Yin ◽  
Yu Zhang ◽  
...  
Keyword(s):  
Whole Genome Sequencing ◽  
Genome Editing ◽  
Genome Sequencing ◽  
Plant Biotechnology ◽  
High Specificity ◽  
Fruit Trees ◽  
Whole Genome ◽  
Nucleotide Polymorphisms ◽  
Indel Mutation ◽  
Target Sites

AbstractThe CRISPR (clustered regularly interspaced short palindromic repeats)-associated protein 9 (Cas9) system is a powerful tool for targeted genome editing, with applications that include plant biotechnology and functional genomics research. However, the specificity of Cas9 targeting is poorly investigated in many plant species, including fruit trees. To assess the off-target mutation rate in grapevine (Vitis vinifera), we performed whole-genome sequencing (WGS) of seven Cas9-edited grapevine plants in which one of two genes was targeted by CRISPR/Cas9 and three wild-type (WT) plants. In total, we identified between 202,008 and 272,397 single nucleotide polymorphisms (SNPs) and between 26,391 and 55,414 insertions/deletions (indels) in the seven Cas9-edited grapevine plants compared with the three WT plants. Subsequently, 3272 potential off-target sites were selected for further analysis. Only one off-target indel mutation was identified from the WGS data and validated by Sanger sequencing. In addition, we found 243 newly generated off-target sites caused by genetic variants between the Thompson Seedless cultivar and the grape reference genome (PN40024) but no true off-target mutations. In conclusion, we observed high specificity of CRISPR/Cas9 for genome editing of grapevine.

scholarly journals A large-scale whole-genome sequencing analysis reveals highly specific genome editing by both Cas9 and Cpf1 nucleases in rice

2018 ◽  
Author(s):  
Xu Tang ◽  
Guanqing Liu ◽  
Jianping Zhou ◽  
Qiurong Ren ◽  
Qi You ◽  
...  
Keyword(s):  
Whole Genome Sequencing ◽  
Genome Editing ◽  
Genome Sequencing ◽  
Large Scale ◽  
High Specificity ◽  
Whole Genome ◽  
Sequencing Analysis ◽  
Guide Rnas ◽  
A Genome ◽  
Multiple Sample

Targeting specificity has been an essential issue for applying genome editing systems in functional genomics, precise medicine and plant breeding. Understanding the scope of off-target mutations in Cas9 or Cpf1-edited crops is critical for research and regulation. In plants, only limited studies had used whole-genome sequencing (WGS) to test off-target effects of Cas9. However, the cause of numerous discovered mutations is still controversial. Furthermore, WGS based off-target analysis of Cpf1 has not been reported in any higher organism to date. Here, we conducted a WGS analysis of 34 plants edited by Cas9 and 15 plants edited by Cpf1 in T0 and T1 generations along with 20 diverse control plants in rice, a major food crop with a genome size of ~380 Mb. The sequencing depth ranged from 45X to 105X with reads mapping rate above 96%. Our results clearly show that most mutations in edited plants were created by tissue culture process, which caused ~102 to 148 single nucleotide variations (SNVs) and ~32 to 83 insertions/deletions (indels) per plant. Among 12 Cas9 single guide RNAs (sgRNAs) and 3 Cpf1 CRISPR RNAs (crRNAs) assessed by WGS, only one Cas9 sgRNA resulted in off-target mutations in T0 lines at sites predicted by computer programs. Moreover, we cannot find evidence for bona fide off-target mutations due to continued expression of Cas9 or Cpf1 with guide RNAs in T1 generation. Taken together, our comprehensive and rigorous analysis of WGS big data across multiple sample types suggests both Cas9 and Cpf1 nucleases are very specific in generating targeted DNA modifications and off-targeting can be avoided by designing guide RNAs with high specificity.

scholarly journals Whole-Genome Sequencing Analysis Reveals High Specificity of CRISPR/Cas9 and TALEN-Based Genome Editing in Human iPSCs

2014 ◽  
Vol 15 (1) ◽  
pp. 12-13 ◽  
Author(s):  
Cory Smith ◽  
Athurva Gore ◽  
Wei Yan ◽  
Leire Abalde-Atristain ◽  
Zhe Li ◽  
...  
Keyword(s):  
Whole Genome Sequencing ◽  
Genome Editing ◽  
Genome Sequencing ◽  
High Specificity ◽  
Whole Genome ◽  
Sequencing Analysis ◽  
Human Ipscs

scholarly journals Fast genetic mapping using insertion-deletion polymorphisms in Caenorhabditis elegans

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ho-Yon Hwang ◽  
Jiou Wang
Keyword(s):  
Caenorhabditis Elegans ◽  
Genetic Mapping ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Genetic Material ◽  
Mapping Method ◽  
Forward Genetics ◽  
Whole Genome ◽  
Nucleotide Polymorphisms ◽  
Large Populations

AbstractGenetic mapping is used in forward genetics to narrow the list of candidate mutations and genes corresponding to the mutant phenotype of interest. Even with modern advances in biology such as efficient identification of candidate mutations by whole-genome sequencing, mapping remains critical in pinpointing the responsible mutation. Here we describe a simple, fast, and affordable mapping toolkit that is particularly suitable for mapping in Caenorhabditis elegans. This mapping method uses insertion-deletion polymorphisms or indels that could be easily detected instead of single nucleotide polymorphisms in commonly used Hawaiian CB4856 mapping strain. The materials and methods were optimized so that mapping could be performed using tiny amount of genetic material without growing many large populations of mutants for DNA purification. We performed mapping of previously known and unknown mutations to show strengths and weaknesses of this method and to present examples of completed mapping. For situations where Hawaiian CB4856 is unsuitable, we provide an annotated list of indels as a basis for fast and easy mapping using other wild isolates. Finally, we provide rationale for using this mapping method over other alternatives as a part of a comprehensive strategy also involving whole-genome sequencing and other methods.

scholarly journals Mycobacterium chimaera genomics with regard to epidemiological and clinical investigations conducted for the open-chest post-surgical Mycobacterium chimaera infections outbreak

2021 ◽  
Author(s):  
Emmanuel Lecorche ◽  
Côme Daniau ◽  
Kevin La ◽  
Faiza Mougari ◽  
Hanaa Benmansour ◽  
...  
Keyword(s):  
Single Nucleotide Polymorphisms ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Clinical Isolates ◽  
Whole Genome ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide ◽  
Healthcare Facilities ◽  
Open Chest

Abstract Background Post-surgical infections due to Mycobacterium chimaera appeared as a novel nosocomial threat in 2015, with a worldwide outbreak due to contaminated heater-cooler units used in open chest surgery. We report the results of investigations conducted in France including whole genome sequencing comparison of patient and HCU isolates. Methods We sought M. chimaera infection cases from 2010 onwards through national epidemiological investigations in healthcare facilities performing cardiopulmonary bypass together with a survey on good practices and systematic heater-cooler unit microbial analyses. Clinical and HCU isolates were subjected to whole genome sequencing analyzed with regards to the reference outbreak strain Zuerich-1. Results Only two clinical cases were shown to be related to the outbreak, although 23% (41/175) heater-cooler units were declared positive for M. avium complex. Specific measures to prevent infection were applied in 89% (50/56) healthcare facilities although only 14% (8/56) of them followed the manufacturer maintenance recommendations. Whole genome sequencing comparison showed that the clinical isolates and 72% (26/36) of heater-cooler unit isolates belonged to the epidemic cluster. Within clinical isolates, 5 to 9 non-synonymous single nucleotide polymorphisms were observed, among which an in vivo mutation in a putative efflux pump gene observed in a clinical isolate obtained for one patient under antimicrobial treatment. Conclusions Cases of post-surgical M. chimaera infections were declared to be rare in France, although heater-cooler units were contaminated as in other countries. Genomic analyses confirmed the connection to the outbreak and identified specific single nucleotide polymorphisms, including one suggesting fitness evolution in vivo.

scholarly journals Whole-Genome Sequencing for Bacterial Strain Typing Using the iSeq100 Platform

2020 ◽  
Vol 41 (S1) ◽  
pp. s434-s434
Author(s):  
Grant Vestal ◽  
Steven Bruzek ◽  
Amanda Lasher ◽  
Amorce Lima ◽  
Suzane Silbert
Keyword(s):  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Outbreak Detection ◽  
Epidemiological Surveillance ◽  
Whole Genome ◽  
Nucleotide Polymorphisms ◽  
Dna Libraries ◽  
Patient Health ◽  
Hospital Acquired ◽  
Reference Genomes

Background: Hospital-acquired infections pose a significant threat to patient health. Laboratories are starting to consider whole-genome sequencing (WGS) as a molecular method for outbreak detection and epidemiological surveillance. The objective of this study was to assess the use of the iSeq100 platform (Illumina, San Diego, CA) for accurate sequencing and WGS-based outbreak detection using the bioMérieux EPISEQ CS, a novel cloud-based software for sequence assembly and data analysis. Methods: In total, 25 isolates, including 19 MRSA isolates and 6 ATCC strains were evaluated in this study: A. baumannii ATCC 19606, B. cepacia ATCC 25416, E. faecalis ATCC 29212, E. coli ATCC 25922, P. aeruginosa ATCC 27853 and S. aureus ATCC 25923. DNA extraction of all isolates was performed on the QIAcube (Qiagen, Hilden, Germany) using the DNEasy Ultra Clean Microbial kit extraction protocol. DNA libraries were prepared for WGS using the Nextera DNA Flex Library Prep Kit (Illumina) and sequenced at 2×150-bp on the iSeq100 according to the manufacturer’s instructions. The 19 MRSA isolates were previously characterized by the DiversiLab system (bioMérieux, France). Upon validation of the iSeq100 platform, a new outbreak analysis was performed using WGS analysis using EPISEQ CS. ATCC sequences were compared to assembled reference genomes from the NCBI GenBank to assess the accuracy of the iSeq100 platform. The FASTQ files were aligned via BowTie2 version 2.2.6 software, using default parameters, and FreeBayes version 1.1.0.46-0 was used to call homozygous single-nucleotide polymorphisms (SNPs) with a minimum coverage of 5 and an allele frequency of 0.87 using default parameters. ATCC sequences were analyzed using ResFinder version 3.2 and were compared in silico to the reference genome. Results: EPISEQ CS classified 8 MRSA isolates as unrelated and grouped 11 isolates into 2 separate clusters: cluster A (5 isolates) and cluster B (6 isolates) with similarity scores of ≥99.63% and ≥99.50%, respectively. This finding contrasted with the previous characterization by DiversiLab, which identified 3 clusters of 2, 8, and 11 isolates, respectively. The EPISEQ CS resistome data detected the mecA gene in 18 of 19 MRSA isolates. Comparative analysis of the ATCCsequences to the reference genomes showed 99.9986% concordance of SNPs and 100.00% concordance between the resistance genes present. Conclusions: The iSeq100 platform accurately sequenced the bacterial isolates and could be an affordable alternative in conjunction with EPISEQ CS for epidemiological surveillance analysis and infection prevention.Funding: NoneDisclosures: None

scholarly journals Transmission of Multidrug/Rifampicin-Resistant Mycobacterium Tuberculosis in Chongqing, China: A Retrospective Observational Study Using Whole-Genome Sequencing

2021 ◽  
Author(s):  
Bing Zhao ◽  
Chunfa Liu ◽  
Jiale Fan ◽  
Aijing Ma ◽  
Wencong He ◽  
...  
Keyword(s):  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Whole Genome ◽  
Nucleotide Polymorphisms ◽  
Resistance Mutations ◽  
Treatment Information ◽  
Recent Transmission ◽  
Drugs Analysis ◽  
Lineage 2 ◽  
And Cluster Analysis

Abstract Background: Multidrug/rifampicin-resistant tuberculosis (MDR/RR-TB) is a global barrel for ‘Stop TB plan’. China has the second highest MDR/RR-TB burden in whole world wide. Understanding the transmission dynamic is facilitated for disease control. Methods: Whole genome sequencing (WGS) data from patients of Chongqing tuberculosis control institute were used for phylogenetic classifications, resistance predictions, and cluster analysis as indicator for recent transmission (RT). Factors associated with MDR/RR-TB were defined by a logistic regression model. Results: A total of 223 cases of MDR/RR-TB were recorded between Jan 1, 2018 and Dec 31, 2020, and 200 cases obtained relevant treatment information. The patients who are older than 55 year old were more likely to suffering from death. 178 MDR/RR strains were obtained WGS data, 152 were classified as lineage 2 strains. 80 (44.9%, 80 of 178) strains were in 20 genomic clusters that differed by 12 or fewer single nucleotide polymorphisms (SNPs), indicating RT. Patients who were infected with lineage 2 strains is a significant factor driving the epidemic towards MDR/RR-TB. Resistance mutations of first-line tuberculosis drugs analysis found that 79 (98.8%) of all 80 strains defined as RT have same mutations among each clusters totally. 55% (44 of 80) of the MDR/RR-TB strains accumulated additional drug resistance mutations along the transmission chain, especially fluoroquinolones (FQs) (63.6%, 28 of 44). Conclusions: The age is the most significant factor that causes death of MDR/RR-TB patients. RT of MDR/RR strains is not only drove the MDR/RR-TB epidemic, but also accumulated more serious resistance along the transmission chains.

scholarly journals Application of Whole Genome Sequencing to Understand Diversity and Presence of Genes Associated with Sanitizer Tolerance in Listeria monocytogenes from Produce Handling Sources

Foods ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2454
Author(s):  
Rebecca N. Bland ◽  
Jared D. Johnson ◽  
Joy G. Waite-Cusic ◽  
Alexandra J. Weisberg ◽  
Elizabeth R. Riutta ◽  
...  
Keyword(s):  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Whole Genome ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide ◽  
Phenotype Screening ◽  
Screening Assays ◽  
Contamination Events ◽  
Sequence Types ◽  
Potential Use

Recent listeriosis outbreaks linked to fresh produce suggest the need to better understand and mitigate L. monocytogenes contamination in packing and processing environments. Using whole genome sequencing (WGS) and phenotype screening assays for sanitizer tolerance, we characterized 48 L. monocytogenes isolates previously recovered from environmental samples in five produce handling facilities. Within the studied population there were 10 sequence types (STs) and 16 cgMLST types (CTs). Pairwise single nucleotide polymorphisms (SNPs) ranged from 0 to 3047 SNPs within a CT, revealing closely and distantly related isolates indicative of both sporadic and continuous contamination events within the facility. Within Facility 1, we identified a closely related cluster (0–2 SNPs) of isolates belonging to clonal complex 37 (CC37; CT9492), with isolates recovered during sampling events 1-year apart and in various locations inside and outside the facility. The accessory genome of these CC37 isolates varied from 94 to 210 genes. Notable genetic elements and mutations amongst the isolates included the bcrABC cassette (2/48), associated with QAC tolerance; mutations in the actA gene on the Listeria pathogenicity island (LIPI) 1 (20/48); presence of LIPI-3 (21/48) and LIPI-4 (23/48). This work highlights the potential use of WGS in tracing the pathogen within a facility and understanding properties of L. monocytogenes in produce settings.

scholarly journals In-Depth Study of a Nosocomial Outbreak Caused by Extensively Drug-Resistant Pseudomonas aeruginosa Using Whole Genome Sequencing Coupled With a Polymerase Chain Reaction Targeting Strain-Specific Single Nucleotide Polymorphisms

2020 ◽  
Vol 189 (8) ◽  
pp. 841-849
Author(s):  
Fermín Acosta ◽  
Ana Fernández-Cruz ◽  
Sandra R Maus ◽  
Pedro J Sola-Campoy ◽  
Mercedes Marín ◽  
...  
Keyword(s):  
Single Nucleotide Polymorphisms ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Whole Genome ◽  
Nucleotide Polymorphisms ◽  
Outbreak Strain ◽  
Single Nucleotide ◽  
Specific Pcr ◽  
Extensively Drug Resistant ◽  
Polymerase Chain

Abstract In 2013–2014, an outbreak involving 14 patients infected by an extensively drug-resistant strain of Pseudomonas aeruginosa was detected in a hospital in Madrid, Spain. Our objective was to evaluate an alternative strategy for investigating the outbreak in depth by means of molecular and genomic approaches. Pulsed-field gel electrophoresis (PFGE) was applied as a first-line approach, followed by a more refined whole genome sequencing analysis. Single nucleotide polymorphisms identified by whole genome sequencing were used to design a specific polymerase chain reaction (PCR) for screening unsuspected cases infected by the outbreak strain. Whole genome sequencing alerted us to the existence of greater genetic diversity than was initially assumed, splitting the PFGE-associated outbreak isolates into 4 groups, 2 of which represented coincidental transmission unrelated to the outbreak. A multiplex allele-specific PCR targeting outbreak-specific single nucleotide polymorphisms was applied to 290 isolates, which allowed us to identify 25 additional cases related to the outbreak during 2011–2017. Whole genome sequencing coupled with an outbreak-strain-specific PCR enabled us to markedly redefine the initial picture of the outbreak by 1) ruling out initially suspected cases, 2) defining likely independent coincidental transmission events, 3) predating the starting point of the outbreak, 4) capturing new unsuspected cases, and 5) revealing that the outbreak was still active.

scholarly journals Whole genome sequencing reveals extensive community-level transmission of group AStreptococcusin remote communities

2016 ◽  
Vol 144 (9) ◽  
pp. 1991-1998 ◽  
Author(s):  
A. C. BOWEN ◽  
T. HARRIS ◽  
D. C. HOLT ◽  
P. M. GIFFARD ◽  
J. R. CARAPETIS ◽  
...  
Keyword(s):  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Whole Genome ◽  
Nucleotide Polymorphisms ◽  
Remote Communities ◽  
Single Nucleotide ◽  
Indigenous Children ◽  
Primary Driver ◽  
Group A ◽  
Sequence Types

SUMMARYImpetigo is common in remote Indigenous children of northern Australia, with the primary driver in this context beingStreptococcus pyogenes[or group AStreptococcus(GAS)]. To reduce the high burden of impetigo, the transmission dynamics of GAS must be more clearly elucidated. We performed whole genome sequencing on 31 GAS isolates collected in a single community from children in 11 households with ⩾2 GAS-infected children. We aimed to determine whether transmission was occurring principally within households or across the community. The 31 isolates were represented by nine multilocus sequence types and isolates within each sequence type differed from one another by only 0–3 single nucleotide polymorphisms. There was evidence of extensive transmission both within households and across the community. Our findings suggest that strategies to reduce the burden of impetigo in this setting will need to extend beyond individual households, and incorporate multi-faceted, community-wide approaches.

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