Jonas Korlach, of PacBio, discusses the use of SMRT sequencing to detect DNA modifications.
Tyson Clark, a scientist at PacBio, demonstrates the detection and identification of damaged DNA using SMRT Sequencing. With the platform’s ability to see base modifications, Clark notes that the polymerase kinetics can distinguish between different types of DNA damage as well — such as oxidative, radiation, and alkylation. This could help in studies of cancer and aging, where DNA damage is an important factor.
Stanford University developmental biologist Lucy Shapiro discusses a collaborative research effort with PacBio sequencing that revealed previously unknown aspects of how chromosome methylation regulates cell cycle progression in Caulobacter. The ability to detect DNA modifications through SMRT Sequencing proved critical in determining methylation states throughout the cell cycle.
Paul Hagerman, MD/PhD, a professor in the biochemistry and molecular medicine department at UC Davis discusses the use of PacBio SMRT sequencing technology for the fragile X gene. Hagerman says the PacBio RS is able to sequence through more than a kilobase of the CGG trinucleotide repeat element underlying Fragile X Syndrome — something no other sequencing platform has achieved. He also plans to use the data to study methylation of this gene, which tends to occur in cases where there are more than 200 copies of the CGG element.
Mario Caccamo, head of bioinformatics at The Genome Analysis Centre (TGAC) in the UK, integrates many different sequencing technologies to get the best of each for optimal genome assemblies, analysis, and annotation. He uses PacBio’s SMRT Sequencing due to its unique long reads for scaffolding and finishing genomes.
Sebastian Suerbaum from Hannover Medical School shows that genome-wide methylation patterns in Helicobacter pylori are highly complex and diverge significantly between strains of the microbe. He presents a full-methylome analysis of two H. pylori strains, finding 32 total methylated motifs with just seven shared between strains. Of the 32 motifs, 11 were new discoveries.
Brian Anton from New England BioLabs presents data on methylation analysis using SMRT Sequencing. He describes both restriction-modification systems and orphan methylases, noting that the number of methylases characterized has more than tripled since the introduction of SMRT Sequencing. The presentation includes a phylogenetic analysis of methyltransferase genes
Garth Ehrlich from the Center for Genomic Sciences at Allegheny Singer Research Institute reports on new studies of pneumococcal epigenetics. Streptococcus pneumonia, which causes more than 1.6 million deaths annually, has a highly plastic genome. Methylation analysis with SMRT Sequencing found a novel modification in addition to the expected epigenetic changes.
Epigenetics expert Michael Jennings from Griffith University first posited the phasevarion, or the phase variable regulon mechanism in host-adapted pathogens. This mechanism switches expression of multiple genes in a coordinated fashion and has significant implications on pathogen virulence. In his talk, Jennings describes the phasevarion and his use of whole methylome data to rapidly identify methylation targets.
In this presentation, Greg Harhay from the USDA offers data on pathogens involved in bovine respiratory disease complex, known as “shipping fever.” His team used PacBio sequencing to analyze several isolates from two different pathogens, looking at their DNA sequence and methylation patterns.
Peter Evans from the US FDA shares insights on whole-genome sequencing for bacteria of importance to public health. Comparing data across PacBio, 454, and MiSeq sequencers, he says having closed genomes, long reads, and methylation patterns are critical for gleaning comprehensive information about a microbe.
Harold Swerdlow, who formerly ran the R&D department at Wellcome Trust Sanger Institute, discusses the Sanger team’s use of the PacBio RS sequencer. He says the system is uniquely suited for de novo sequencing and genome assembly, methylation pattern identification, and low-level variant detection because of its long reads and high-accuracy, single-molecule sequencing. At Sanger, that makes a real difference for the large-scale projects they have in cancer biology, pathogen sequencing, and human genetics.
UC Davis’s Bart Weimer describes foodborne pathogens and their proclivity for rapid genome rearrangement. The 100K Pathogen Genome Project he leads is using PacBio long-read sequencing to close genomes and analyze methylation; Weimer reports that his team has already discovered new epigenetic modifications in Salmonella and Listeria with the technology.
In this AGBT plenary talk, Jonas Korlach presented a number of collaborative studies between PacBio and other institutions to make use of highly accurate, long-read sequence data, which has led to a revival of finished genomes. Examples from the infectious disease or pathogen realm included Pertussis, Salmonella, and Listeria, all of which now have closed genomes from PacBio-generated data. Korlach also reported on epigenomic information in Salmonella and Listeria, indicating potential new forms of DNA modifications.
How does the PacBio sequencer produce epigenetic data? CSO Jonas Korlach describes how the technology works, which DNA modifications can be detected, and gives examples of kinetic signatures for various modifications and their associated target motifs.