Structural variants (SVs) – genomic differences =50 base pairs – are few by count compared to single nucleotide variants (SNVs) and indels but include most of the base pairs that differ between two humans.
Structural variation accounts for much of the variation among human genomes. Structural variants of all types are known to cause Mendelian disease and contribute to complex disease. Learn how long-read sequencing is enabling detection of the full spectrum of structural variants to advance the study of human disease, evolution and genetic diversity.
PacBio highly accurate long reads – HiFi reads – offer a single-platform solution for rare and inherited disease research, elucidating suspected genetic causes of disease in up to ~50% of cases that have not previously been explained using short-read exome or whole genome sequencing. PacBio offers an efficient workflow, developed in collaboration with Children’s Mercy Kansas City, which provides a scalable solution for sequencing 100s to 1000s of whole human genomes per year on the Sequel II and Sequel IIe Systems.
With highly accurate long reads (HiFi reads) from the Sequel II or IIe Systems you can comprehensively detect variants in 100s to 1000s of genomes in a year. HiFi reads provide high precision and recall for single nucleotide variants (SNVs), indels, structural variants (SVs), and copy number variants (CNVs), including in difficult-to-map repetitive regions.
Melissa Laird Smith discussed how the Icahn School of Medicine at Mount Sinai uses long-read sequencing for translational research. She gave several examples of targeted sequencing projects run on the Sequel System including CYP2D6, phased mutations of GLA in Fabry’s disease, structural variation breakpoint validation in glioblastoma, and full-length immune profiling of TCR sequences.
Explore human genetic variation and learn how SMRT Sequencing uncovers the full spectrum of structural variation to advance understanding of genetic disease and broaden our knowledge of human diversity.
Most of the basepairs that differ between two human genomes are in intermediate-sized structural variants (50 bp to 5 kb), which are too small to detect with array CGH but too large to reliably discover with short-read NGS. PacBio Single Molecule, Real-Time (SMRT) Sequencing fills this technology gap. SMRT Sequencing detects tens of thousands of structural variants in a human genome, approximately five times the sensitivity of short-read NGS. To discover variants using SMRT Sequencing, we have developed pbsv, which is available in version 5 of the PacBio SMRT Link software suite. The pbsv algorithm applies a sequence of stages:…
In this ASHG 2017 presentation, Jonas Korlach, the CSO of PacBio shared updates on three applications featuring SMRT Sequencing on the Sequel System, highlighting structural variant detection, targeted sequencing and the Iso-Seq method of RNA sequencing. He provided details on structural variant calling using pbsv to call insertions and deletions and compared PacBio variant calling with other technologies. Korlach described how targeted sequencing can be used to interrogate repeat expansions, detect and phase minor variants and can access medically relevant but previously inaccessible gene targets. He presented research featuring the Iso-Seq method that identified isoforms, corrected previous isoform annotations and…
In this ASHG 2017 presentation, Han Brunner of Radboud University Medical Center presented research using SMRT Sequencing to detect structural variants to uncover the genetic causes of intellectual disability. He shared that long-read sequencing enabled detection of 25,000 structural variants per genome. Brunner presented data from patient trios to identify de novo structural variant candidates and ongoing validation work to determine the causative mutations of intellectual disability.
In this presentation Fritz Sedlazeck describes his latest work to obtain comprehensive genomes leveraging long-read sequencing and linked reads.
Structural variants (SVs, differences >50 base pairs) account for most of the base pairs that differ between two human genomes, and are known to cause over 1,000 genetic disorders including ALS, schizophrenia, and hereditary cancer. Yet, SVs remain overlooked in human genetic research studies due to the limited power of short-read sequencing methods (exome and whole genome sequencing) to resolve large variants, which often involve repetitive DNA. Recent advances in long-read sequencing have made it possible to detect the over 20,000 SVs that are now known to exist in a human genome. Corresponding advances in long-read SV calling algorithms have…
In this video, Aaron Wenger, a research scientist at PacBio, describes the use of long-read SMRT Sequencing to detect structural variants in the human genome. He shares that structural variations – such as insertions and deletions – impact human traits, cause disease, and differentiate humans from other species. Wenger highlights the use of SMRT Sequencing and structural variant calling software tools in a collaboration with Stanford University which identified a disease-causing genetic mutation.
In this ASHG workshop presentation, Stuart Scott of the Icahn School of Medicine at Mount Sinai, presented on using the PacBio system for amplicon sequencing in pharmacogenomics and clinical genomics workflows. Accurate, phased amplicon sequence for the CYP2D6 gene, for example, has allowed his team to reclassify up to 20% of samples, providing data that’s critical for drug metabolism and dosing. In clinical genomics, Scott presented several case studies illustrating the utility of highly accurate, long-read sequencing for assessing copy number variants and for confirming a suspected medical diagnosis in rare disease patients. He noted that the latest Sequel System…
In this PacBio User Group Meeting presentation, Jonas Korlach and Roberto Lleras share the latest updates to the structural variation application and analysis tools.
As they migrated out of Africa and into Europe and Asia, anatomically modern humans interbred with archaic hominins, such as Neanderthals and Denisovans. The result of this genetic introgression on the recipient populations has been of considerable interest, especially in cases of selection for specific archaic genetic variants. Hsieh et al. characterized adaptive structural variants and copy number variants that are likely targets of positive selection in Melanesians. Focusing on population-specific regions of the genome that carry duplicated genes and show an excess of amino acid replacements provides evidence for one of the mechanisms by which genetic novelty can arise…