Day 3 of the Advances in Genome Biology and Technology meeting in Marco Island began with an announcement that next year the meeting would be held in Orlando due to hotel renovations, eliciting a groan from the audience. The meeting will come back to Marco Island in 2017.
Today’s plenary session speakers all presented work with a clinical focus, acknowledgement by the conference organizers about the direction of genome sequencing. The first speaker, Gail Jarvik, head of medical genetics at the University of Washington Medical Center presented on lessons learned from the Clinical Sequencing Exploratory Research (CSER) Consortium, marketed as ‘Hail CSER’. CSER is a national consortium of projects aimed at sharing innovations and best practices in the integration of genomic sequencing into clinical care. CSER has established a list of 112 actionable genes, some overlapping with the American College of Medical Genetics (ACMG) list. The CSER group annotated pathogenic and novel variants of the Exome Variant Server (EVS) to estimate rates in individuals of European and African ancestry.
The next talk was by Euan Ashley on moving toward clinical grade whole genome sequencing. He started by describing the genome as complex, full of repeats, duplications and paralogous sequences, giving him ‘a cold sweat at night’. He gave an example of a study with 12 adult participants who underwent WGS and described how clinical grade sequencing demands consistency in reporting. Most variants annotated as pathogenic were downgraded after manual review, but this takes lots of time. 12 individuals with 1,000 variants took around 1 hour per variant. In this case the use of WGS was associated with incomplete coverage of inherited disease genes, low reproducibility of detectable genetic variation and uncertainty about clinically reportable findings. He commented that new algorithms would be needed to address these problems and that ‘we’re at the beginning of genomics medicine’. Parts of his talk can be seen in his presentation at PMWC last month.
The last presentation before the break was by Levi Garraway who discussed the goal of cancer precision medicine to develop new therapeutics and combinations against molecular defined tumors. He mentioned that there are many discovery opportunities in clinical cancer genomics especially in terms of response and resistance to new therapies. Garraway sequenced the genomes of 57 prostate tumors and matched normal tissues to study somatic alterations. His model suggests that chormoplexy induces considerable genomic derangement over a relatively few number of events in prostate cancer supporting a model of punctuated cancer evolution. He introduced a 10X Genomics approach for phasing of large – 100 kb regions with exonic baits to obtain rearrangement information for chromoplexy. In the end he emphasized the importance of RNA-Seq profiling in conjunction with DNA sequencing for translational medicine to be relevant.
After the break, Stephen Kingsmore gave a presentation on rapid genome sequencing for genetic disease diagnostics in neonatal intensive care units. Kingsmore began the talk by describing how newborn screening (NBS) and early diagnosis reduces morbidity and mortality. NGS of 60 genetic diseases identifies ~5,000 affected newborns each year. He described how rapid genome sequencing (RGS) has the potential to improve NBS to most genetic diseases in newborns admitted to level II-IV NICUs. He mentioned a ‘ultra rapid’ sequencing pipeline he developed along with Illumina that takes 28 hours to go from sample to variant annotation (not publically available). He also discussed NSIGHT, a consortium for newborn sequencing sponsored by the NIH to understand the role of genome sequencing. More details can be found on the NHGRI page.
The last two plenary talks were by Christian Matranga and Malachi Griffith. Matranga described the clinical sequencing of viral genomes as important to understanding the evolution and transmission of the pathogen and the ability to inform on surveillance and therapeutic development. They developed a sequencing approach that combines RNAse H based depletion of rRNA with random primed cDNA RNA-seq to detect and assemble genomes from divergent lineages. They sequenced ~300 Lassa (LASV) and ~100 Ebola (EBOV) genomes. We describe some of their efforts in an earlier post called, Sequencing Suggests the Ebola Virus Genome is Changing. Be sure to read the New Yorker reference, it’s compelling!
Griffith’s talk was on optimizing genome sequencing and analysis. He makes the point that while most tumors are sequenced by exome sequencing at 75-100x mean coverage or by whole genome sequencing (WGS) to 30-50x mean coverage, detection of low frequency mutations require greater depth. He performed deep sequencing of an acute myeloid leukemia (AML) by WGS up to 350X, whole exome to 300X and using a capture panel of ~260 recurrently mutated AML genes to ~10,000x coverage. He found that deeper sequencing revealed more driver variants and improved the assignment of variants to clonal clusters. Checkout his animation of WGS depth down-sampling.
After lunch began the ‘Bronze sponsor workshops’, essentially the talks you pay >$40K to give. The most interesting was the last by 10X Genomics, mainly because as @bioinformer put it, “10X Genomics is the new princess of the AGBT ball”. First, check out the video that received a round of applause from the AGBT crowd: Changing the Definition of Sequencing. They announced their instrument would be available in Q2 this year, cost ~$75K and $500 / sample. This brings the question whether 10X Genomic’s microfluidic platform offers greater potential than Molecule. What are the implications for Illumina or PacBio? To learn more check out Keith Robison’s insightful post detailing all there is currently known about 10X Genomics.
After dinner began concurrent sessions on technology, genomic medicine and transcriptomics. Hopefully someone else will post details about the genomic medicine and transcriptomics sessions. The technology session began with Iain Macaulay describing G&T-seq, separation and parallel sequencing of genomes and transcriptomes of single cells. This was the first talk this year at AGBT with an embargo, no tweets were allowed. So rather than go into details, we did find this lecture online. The next talk was by Alexandre Melnikov on MITE-Seq, an approach to site directed mutagenesis referred to as Mutagenesis by Integrated TiLEs. MITE facilitates structure-function studies of proteins at higher resolution than typical site directed approaches. To read more check out their paper published last year in Nucleic Acid Research. Andrea Kohn, then described single-cell methylome profiling of Aplysia neurons. Using methyl-dip and bisulfite sequencing she achieved >20x coverage for each neuron and then added RNA-seq providing the first methylome and transcriptome from a single neuron. Next up was Sara Goodwin who gave an in depth analysis of the Oxford MinION Device for de novo and cDNA sequencing. She sequenced the yeast strain W303 to over 120x coverage and was able to achieve up to 80% aligned reads. She mentioned that identifying the right aligner was still a work in progress but overall found promise in the technology for long read sequencing, de novo assembly and splice site id.
Tomorrow’s plenary talks are the second installment of genomics, ‘Genomics II’ with presentations by Michael Fischback, Rob Knight, Chris Mason, and Gene Myers, excellent lineup to close the final day of AGBT. Checkout our earlier posts if you’ve missed day 1 or day 2.