Single Molecule, Real-Time (SMRT) Sequencing uses the natural process of DNA replication to sequence long fragments of native DNA in order to produce highly accurate long reads, or HiFi reads. As such, starting with high-quality, high molecular weight (HMW) genomic DNA (gDNA) will result in longer libraries and better performance during sequencing. This technical note is intended to give recommendations, tips and tricks for the extraction of DNA, as well as assessing and preserving the quality and size of your DNA sample to be used for HiFi sequencing.
DNA is under constant stress from both endogenous and exogenous sources. DNA base modifications resulting from various types of DNA damage are wide-spread and play important roles in affecting physiological states and disease phenotypes. Examples include oxidative damage (8- oxoguanine, 8-oxoadenine; aging, Alzheimer’s, Parkinson’s), alkylation (1-methyladenine, 6-O- methylguanine; cancer), adduct formation (benzo[a]pyrene diol epoxide (BPDE), pyrimidine dimers; smoking, industrial chemical exposure, chemical UV light exposure, cancer), and ionizing radiation damage (5-hydroxycytosine, 5- hydroxyuracil, 5-hydroxymethyluracil; cancer). Currently, these and other products of DNA damage cannot be sequenced with existing sequencing methods. In contrast, single molecule, real-time (SMRT) DNA sequencing can report…
Single Molecule, Real-Time (SMRT) Sequencing holds promise for addressing new frontiers in large genome complexities, such as long, highly repetitive, low-complexity regions and duplication events, and differentiating between transcript isoforms that are difficult to resolve with short-read technologies. We present solutions available for both reference genome improvement (>100 MB) and transcriptome research to best leverage long reads that have exceeded 20 Kb in length. Benefits for these applications are further realized with consistent use of size-selection of input sample using the BluePippin™ device from Sage Science. Highlights from our genome assembly projects using the latest P5-C3 chemistry on model organisms…
SFAF 2014 Presentation Slides: James Gurtowski of Cold Spring Harbor Laboratory (CSHL) shared assembly results for a variety of eukaryotic genomes, including yeast, arabidopsis, and rice.
Single Molecule, Real-Time (SMRT) Sequencing holds promise for addressing new frontiers to understand molecular mechanisms in evolution and gain insight into adaptive strategies. With read lengths exceeding 10 kb, we are able to sequence high-quality, closed microbial genomes with associated plasmids, and investigate large genome complexities, such as long, highly repetitive, low-complexity regions and multiple tandem-duplication events. Improved genome quality, observed at 99.9999% (QV60) consensus accuracy, and significant reduction of gap regions in reference genomes (up to and beyond 50%) allow researchers to better understand coding sequences with high confidence, investigate potential regulatory mechanisms in noncoding regions, and make inferences…
Single Molecule, Real-Time (SMRT) Sequencing provides efficient, streamlined solutions to address new frontiers in plant genomes and transcriptomes. Inherent challenges presented by highly repetitive, low-complexity regions and duplication events are directly addressed with multi- kilobase read lengths exceeding 8.5 kb on average, with many exceeding 20 kb. Differentiating between transcript isoforms that are difficult to resolve with short-read technologies is also now possible. We present solutions available for both reference genome and transcriptome research that best leverage long reads in several plant projects including algae, Arabidopsis, rice, and spinach using only the PacBio platform. Benefits for these applications are further…
The developments in DNA sequencing technology over the past several years have enabled large number of scientists to obtain sequences for the genomes of their interest at a fairly low cost. Illumina Sequencing was the dominant whole genome sequencing technology over the past few years due to its low cost. The Illumina reads are short (up to 300bp) and thus most of those draft genomes produced from Illumina data are very fragmented which limits their usability in practical scenarios. Longer reads are needed for more contiguous genomes. Recently Pacbio sequencing made significant advances in developing cost-effective long-read (>10000bp) sequencing technology…
PacBio Sequencing is characterized by very long sequence reads (averaging > 10,000 bases), lack of GC-bias, and high consensus accuracy. These features have allowed the method to provide a new gold standard in de novo genome assemblies, producing highly contiguous (contig N50 > 1 Mb) and accurate (> QV 50) genome assemblies. We will briefly describe the technology and then highlight the full workflow, from sample preparation through sequencing to data analysis, on examples of insect genome assemblies, and illustrate the difference these high-quality genomes represent with regard to biological insights, compared to fragmented draft assemblies generated by short-read sequencing.
To start Day 2 of the PacBio User Group Meeting, Jonas Korlach, PacBio CSO, provides an update on lowering DNA input amounts for SMRT Sequencing workflows. Updates include a more robust shearing method, a revised AMPure size selection, and introduction of multiplexing low input samples. Finally, the use of HiFi sequencing with low input results in a more complete genome assembly. Jonas closes by mentioning that the low DNA input protocol is now available and further advancements to lower input requirements even more will open opportunities for different samples, such as cancer needle biopsies.
To start Day 1 of the PacBio User Group Meeting, Jonas Korlach, PacBio CSO, provides an update on the latest releases and performance metrics for the Sequel II System. The longest reads generated on this system with the SMRT Cell 8M now go beyond 175,000 bases, while maintaining extremely high accuracy. HiFi mode, for example, uses circular consensus sequencing to achieve accuracy of Q40 or even Q50.
In this PacBio User Group Meeting presentation, Eugenio Daviso from Covaris talks about the use of adaptive focused acoustics for gentle cell lysis and extraction of high molecular weight DNA.
In this webinar you will hear how several researchers have overcome the challenges of sequencing organisms with small body size using the new low and ultra-low DNA input methods from PacBio. Learn about the advantages of using highly accurate long reads (HiFi reads) to sequence and de novo assemble genomes of single individuals.
The widespread occurrence of repetitive stretches of DNA in genomes of organisms across the tree of life imposes fundamental challenges for sequencing, genome assembly, and automated annotation of genes and proteins. This multi-level problem can lead to errors in genome and protein databases that are often not recognized or acknowledged. As a consequence, end users working with sequences with repetitive regions are faced with ‘ready-to-use’ deposited data whose trustworthiness is difficult to determine, let alone to quantify. Here, we provide a review of the problems associated with tandem repeat sequences that originate from different stages during the sequencing-assembly-annotation-deposition workflow, and…
Domestication of clonally propagated crops such as pineapple from South America was hypothesized to be a ‘one-step operation’. We sequenced the genome of Ananas comosus var. bracteatus CB5 and assembled 513?Mb into 25 chromosomes with 29,412 genes. Comparison of the genomes of CB5, F153 and MD2 elucidated the genomic basis of fiber production, color formation, sugar accumulation and fruit maturation. We also resequenced 89 Ananas genomes. Cultivars ‘Smooth Cayenne’ and ‘Queen’ exhibited ancient and recent admixture, while ‘Singapore Spanish’ supported a one-step operation of domestication. We identified 25 selective sweeps, including a strong sweep containing a pair of tandemly duplicated…
Although many ß-agarases that hydrolyze the ß-1,4 linkages of agarose have been biochemically characterized, only three a-agarases that hydrolyze the a-1,3 linkages are reported to date. In this study, a new a-agarase, AgaWS5, from Catenovulum sediminis WS1-A, a new agar-degrading marine bacterium, was biochemically characterized. AgaWS5 belongs to the glycoside hydrolase (GH) 96 family. AgaWS5 consists of 1295 amino acids (140 kDa) and has the 65% identity to an a-agarase, AgaA33, obtained from an agar-degrading bacterium Thalassomonas agarivorans JAMB-A33. AgaWS5 showed the maximum activity at a pH and temperature of 8 and 40 °C, respectively. AgaWS5 showed a cold-tolerance, and…