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Accessing and visualizing genomics data
Jim Noonan GENE 760
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A working definition of genomics
The global study of how biological information is encoded in genome sequence Genes Regulatory sequences Genetic variation How this information is read out to produce distinct biological outcomes Gene expression and regulation Cellular identity, differentiation and development Phenotypic variation among individuals and species
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Genomes are vast information repositories
Human 3 Gb kb = 1000 bp Mb = 1x106 bp Gb = 1x109 bp Tb = 1x1012 bp Pb = 1x1015 bp 1 Gb 10 Gb 100 Gb
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Sequencing the reference human genome (1990-present; ‘finished’ 2003)
Industrialization of Sanger sequencing, library construction, sample preparation, analysis, etc. $3 billion total cost 1 Gb/month at largest centers (2005) YCGA = 9.6 Tb per month (2011)
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Reference genomes
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Genome assembly and annotation
3 Gb >>109 sequencing reads 36 bp - 1 kb
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Genome assembly Scaffold_0: 12,865,123 – 12,965-110
Assembly quality criteria: Accuracy: number of errors (Human << 1/100,000 bp) Contiguity: number of gaps (Human: est. 357) Generate reads Find overlapping reads Assemble reads into contigs contig Coverage: Average number of reads representing a particular position in the assembly Human, Mouse, Rat: > 20x Chimpanzee: ~6x Squirrel: ~2x Join contigs into scaffolds scaffold mate pair Scaffold_0: 12,865,123 – 12, Join scaffolds into “finished” sequence anchored on chromosomes AGTTGTATTATTAGAAACTGAGGGCTAAAAACTGTGCACATACACAGACACACATATTATTTTAATATAGATTTTCAATAATTGGTCTAGGATAAGGATAATATACAG Chr5: 133,876,119 – 134,876,119 7
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ATATCATGCTTGTCATTCGTTTATCAGAGGCCAAATGTTTTTCTTTGTAAACGTGTGTAAAACATTCTCAGAATTTTAAACAATAACAAATCAGGGCTGAATGTGGCCAACATGCAAAGAGGAAATCTCCCATCTGTCCAAATCAAACAGTTGTATTATTAGAAACTGAGGGCTAAAAACTGTGCACATACACAGACACACATATTATTTTAATATAGATTTTCAATAATTGGTCTAGGATAAGGATAATATACAGAGAACATGCCAAAAGTTTAAGCAAGAAGAAAACAAAGACTGTTACTATGGAAAAATGAAAATAGATTTTAAAACATGTTAATTCACGTTACTTTTTGTTAAATTTACTTTTCTTCTTTCACTTCTTACCTGTCAATGTTATTAATATTTTTAGGAACAATAAATCACATTAATTCCTTATCTCATGTGAAATTTCATATTTATGATTGATACCTTTAAATGTCATTTGTTGAAGGAAGATTATTCATTTTTTCATTCAATAAATATTTTTTAGAATAATAAGTCCCAGGCACAAGACCAGTATTATGTTCTAGGCATTGGGGATACCATGTTCACAAGACAGACTATGATTTACAGGATCAGATGTGGACTCTCAAATTCGACTGAGAATAAAACAGACACTAAACAAGTAAATAAAGTTAATTTCAAGTTGTAATTGATGCTAGAAAGACAATGAAACAGAGCCATGTGACCAATGAGAGAGATGAGGGTGGCAGCAGCCTGTTTTAGATAAGGTACCTGATTGGTGGGATTGGAAGACCTCTCTGAGATTAGTGTCTTCAGATATGCCTTAATGATATGAAAGAACCATTCATGGGAAGGCCTAGCATTAAAAACCGTCTAGGCAGAATGAGCAGCAAGTGCAAGGGTCCTGGATAGGAATGAGCTGGATATACTCAAGGAAGAAAGAGAAACTATGGAAAAATGAAAATAGATTTTAAAACATGTTAATTCACGTTACTTTTTGTTAAATTTACTTTTCTTCTTTCACTTCTTACCTGTCAATGTTATTAATATTTTTAGGAACAATAAATCACATTAATTCCTTATCTCATGTGAAATTTCATATTTATGATTGATACCTTTAAATGTCATTTGTTGAAGGAAGATTATTCATTTTTTCATTCAATAAATATTTTTTAGAATAATAAGTCCCAGGCACAAGACCAGTATTATGTTCTAGGCATTGGGGATACCATGTTCACAAGACAGACTATGATTTACAGGATCAGATGTGGACTCTCAAATTCGACTGAGAATAAAACAGACACTAAACAAGTAAATAAAGTTAATTTCAAGTTGTAATTGATGCTACTATGGAAAAATGAAAATAGATTTTAAAACATGTTAATTCACGTTACTTTTTGTTAAATTTACTTTTCTTCTTTCACTTCTTACCTGTCAATGTTATTAATATTTTTAGGAACAATAAATCACATTAATTCCTTATCTCATGTGAAATTTCATATTTATGATTGATACCTTTAAATGTCATTTGTTGAAGGAAGATTATTCATTTTTTCATTCAATAAATATTTTTTAGAATAATAAGTCCCAGGCACAAGACCAGTATTATGTTCTAGGCATTGGGGATACCATGTTCACAAGACAGACTATGATTTACAGGATCAGATGTGGACTCTCAAATTCGACTGAGAATAAAACAGACACAAACAAGTAAATAAAGTTAATTTCAAGTTGTAATTGATGCTATCCCAGGCACAAGACCAGTATTATGTTCTAGGCATTGGGGATACCATTACCTGTCAATGTTATTAATATTTTTAGGAACAATAAATCACATTAATTCCAACATGCAAAGAGGAAATCTCCATATCATGCTTGTCATTCGTTTATCAGAGGCCAAATGTTTTTCTTTGTAAACGTGTGTAAAACATTCTCAGAATTTTAAACAATAACAAATCAGGGCTGAATGTGGCCAACATGCAAAGAGGAAATCTCCCATCTGTCCAAATCAAACAGTTGTATTATTAGAAACTGAGGGCTAAAAACTGTGCACATACACAGACACACATATTATTTTAATATAGATTTTCAATAATTGGTCTAGGATAAGGATAATATACAGAGAACATGCCAAAAGTTTAAGCAAGAAGAAAACAAAGACTGTTACTATGGAAAAATGAAAATAGATTTTAAAACATGTTAATTCACGTTACTTTTTGTTAAATTTACTTTTCTTCTTTCACTTCTTACCTGTCAATGTTATTAATATTTTTAGGAACAATAAATCACATTAATTCCTTATCTCATGTGAAATTTCATATTTATGATTGATACCTTTAAATGTCATTTGTTGAAGGAAGATTATTCATTTTTTCATTCAATAAATATTTTTTAGAATAATAAGTCCCAGGCACAAGACCAGTATTATGTTCTAGGCATTGGGGATACCATGTTCACAAGACAGACTATGATTTACAGGATCAGATGTGGACTCTCAAATTCGACTGAGAATAAAACAGACACTAAACAAGTAAATAAAGTTAATTTCAAGTTGTAATTGATGCTAGAAAGACAATGAAACAGAGCCATGTGACCAATGAGAGAGATGAGGGTGGCAGCAGCCTGTTTTAGATAAGGTACCTGATTGGTGGGATTGGAAGACCTCTCTGAGATTAGTGTCTTCAGATATGCCTTAATGATATGAAAGAACCATTCATGGGAAGGCCTAGCATTAAAAACCGTCTAGGCAGAATGAGCAGCAAGTGCAAGGGTCCTGGATAGGAATGAGCTGGATATACTCAAGGAAGAAAGAGAAACTATGGAAAAATGAAAATAGATTTTAAAACATGTTAATTCACGTTACTTTTTGTTAAATTTACTTTTCTTCTTTCACTTCTTACCTGTCAATGTTATTAATATTTTTAGGAACAATAAATCACATTAATTCCTTATCTCATGTGAAATTTCATATTTATGATTGATACCTTTAAATGTCATTTGTTGAAGGAAGATTATTCATTTTTTCATTCAATAAATATTTTTTAGAATAATAAGTCCCAGGCACAAGACCAGTATTATGTTCTAGGCATTGGGGATACCATGTTCACAAGACAGACTATGATTTACAGGATCAGATGTGGACTCTCAAATTCGACTGAGAATAAAACAGACACTAAACAAGTAAATAAAGTTAATTTCAAGTTGTAATTGATGCTACTATGGAAAAATGAAAATAGATTTTAAAACATGTTAATTCACGTTACTTTTTGTTAAATTTACTTTTCTTCTTTCACTTCTTACCTGTCAATGTTATTAATATTTTTAGGAACAATAAATCACATTAATTCCTTATCTCATGTGAAATTTCATATTTATGATTGATACCTTTAAATGTCATTTGTTGAAGGAAGATTATTCATTTTTTCATTCAATAAATATTTTTTAGAATAATAAGTCCCAGGCACAAGACCAGTATTATGTTCTAGGCATTGGGGATACCATGTTCACAAGACAGACTATGATTTACAGGATCAGATGTGGACTCTCAAATTCGACTGAGAATAAAACAGACACAAACAAGTAAATAAAGTTAATTTCAAGTTGTAATTGATGCTATCCCAGGCACAAGACCAGTATTATGTTCTAGGCATTGGGGATACCATTACCTGTCAATGTTATTAATATTTTTAGGAACAATAAATCACATTAATTCCAACATGCAAAGAGGAAATCTCCATATCATGCTTGTCATTCGTTTATCAGAGGCCAAATGTTTTTCTTTGTAAACGTGTGTAAAACATTCTCAGAATTTTAAACAATAACAAATCAGGGCTGAATGTGGCCAACATGCAAAGAGGAAATCTCCCATCTGTCCAAATCAAACAGTTGTATTATTAGAAACTGAGGGCTAAAAACTGTGCACATACACAGACACACATATTATTTTAATATAGATTTTCAATAATTGGTCTAGGATAAGGATAATATACAGAGAACATGCCAAAAGTTTAAGCAAGAAGAAAACAAAGACTGTTACTATGGAAAAATGAAAATAGATTTTAAAACATGTTAATTCACGTTACTTTTTGTTAAATTTACTTTTCTTCTTTCACTTCTTACCTGTCAATGTTATTAATATTTTTAGGAACAATAAATCACATTAATTCCTTATCTCATGTGAAATTTCATATTTATGATTGATACCTTTAAATGTCATTTGTTGAAGGAAGATTATTCATTTTTTCATTCAATAAATATTTTTTAGAATAATAAGTCCCAGGCACAAGACCAGTATTATGTTCTAGGCATTGGGGATACCATGTTCACAAGACAGACTATGATTTACAGGATCAGATGTGGACTCTCAAATTCGACTGAGAATAAAACAGACACTAAACAAGTAAATAAAGTTAATTTCAAGTTGTAATTGATGCTAGAAAGACAATGAAACAGAGCCATGTGACCAATGAGAGAGATGAGGGTGGCAGCAGCCTGTTTTAGATAAGGTACCTGATTGGTGGGATTGGAAGACCTCTCTGAGATTAGTGTCTTCAGATATGCCTTAATGATATGAAAGAACCATTCATGGGAAGGCCTAGCATTAAAAACCGTCTAGGCAGAATGAGCAGCAAGTGCAAGGGTCCTGGATAGGAATGAGCTGGATATACTCAAGGAAGAAAGAGAAACTATGGAAAAATGAAAATAGATTTTAAAACATGTTAATTCACGTTACTTTTTGTTAAATTTACTTTTCTTCTTTCACTTCTTACCTGTCAATGTTATTAATATTTTTAGGAACAATAAATCACATTAATTCCTTATCTCATGTGAAATTTCATATTTATGATTGATACCTTTAAATGTCATTTGTTGAAGGAAGATTATTCATTTTTTCATTCAATAAATATTTTTTAGAATAATAAGTCCCAGGCACAAGACCAGTATTATGTTCTAGGCATTGGGGATACCATGTTCACAAGACAGACTATGATTTACAGGATCAGATGTGGACTCTCAAATTCGACTGAGAATAAAACAGACACTAAACAAGTAAATAAAGTTAATTTCAAGTTGTAATTGATGCTACTATGGAAAAATGAAAATAGATTTTAAAACATGTTAATTCACGTTACTTTTTGTTAAATTTACTTTTCTTCTTTCACTTCTTACCTGTCAATGTTATTAATATTTTTAGGAACAATAAATCACATTAATTCCTTATCTCATGTGAAATTTCATATTTATGATTGATACCTTTAAATGTCATTTGTTGAAGGAAGATTATTCATTTTTTCATTCAATAAATATTTTTTAGAATAATAAGTCCCAGGCACAAGACCAGTATTATGTTCTAGGCATTGGGGATACCATGTTCACAAGACAGACTATGATTTACAGGATCAGATGTGGACTCTCAAATTCGACTGAGAATAAAACAGACACAAACAAGTAAATAAAGTTAATTTCAAGTTGTAATTGATGCTATCCCAGGCACAAGACCAGTATTATGTTCTAGGCATTGGGGATACCATTACCTGTCAATGTTATTAATATTTTTAGGAACAATAAATCACATTAATTCCAACATGCAAAGAGGAAATCTCCATATCATGCTTGTCATTCGTTTATCAGAGGCCAAATGTTTTTCTTTGTAAACGTGTGTAAAACATTCTCAGAATTTTAAACAATAACAAATCAGGGCTGAATGTGGCCAACATGCAAAGAGGAAATCTCCCATCTGTCCAAATCAAACAGTTGTATTATTAGAAACTGAGGGCTAAAAACTGTGCACATACACAGACACACATATTATTTTAATATAGATTTTCAATAATTGGTCTAGGATAAGGATAATATACAGAGAACATGCCAAAAGTTTAAGCAAGAAGAAAACAAAGACTGTTACTATGGAAAAATGAAAATAGATTTTAAAACATGTTAATTCACGTTACTTTTTGTTAAATTTACTTTTCTTCTTTCACTTCTTACCTGTCAATGTTATTAATATTTTTAGGAACAATAAATCACATTAATTCCTTATCTCATGTGAAATTTCATATTTATGATTGATACCTTTAAATGTCATTTGTTGAAGGAAGATTATTCATTTTTTCATTCAATAAATATTTTTTAGAATAATAAGTCCCAGGCACAAGACCAGTATTATGTTCTAGGCATTGGGGATACCATGTTCACAAGACAGACTATGATTTACAGGATCAGATGTGGACTCTCAAATTCGACTGAGAATAAAACAGACACTAAACAAGTAAATAAAGTTAATTTCAAGTTGTAATTGATGCTAGAAAGACAATGAAACAGAGCCATGTGACCAATGAGAGAGATGAGGGTGGCAGCAGCCTGTTTTAGATAAGGTACCTGATTGGTGGGATTGGAAGACCTCTCTGAGATTAGTGTCTTCAGATATGCCTTAATGATATGAAAGAACCATTCATGGGAAGGCCTAGCATTAAAAACCGTCTAGGCAGAATGAGCAGCAAGTGCAAGGGTCCTGGATAGGAATGAGCTGGATATACTCAAGGAAGAAAGAGAAACTATGGAAAAATGAAAATAGATTTTAAAACATGTTAATTCACGTTACTTTTTGTTAAATTTACTTTTCTTCTTTCACTTCTTACCTGTCAATGTTATTAATATTTTTAGGAACAATAAATCACATTAATTCCTTATCTCATGTGAAATTTCATATTTATGATTGATACCTTTAAATGTCATTTGTTGAAGGAAGATTATTCATTTTTTCATTCAATAAATATTTTTTAGAATAATAAGTCCCAGGCACAAGACCAGTATTATGTTCTAGGCATTGGGGATACCATGTTCACAAGACAGACTATGATTTACAGGATCAGATGTGGACTCTCAAATTCGACTGAGAATAAAACAGACACTAAACAAGTAAATAAAGTTAATTTCAAGTTGTAATTGATGCTACTATGGAAAAATGAAAATAGATTTTAAAACATGTTAATTCACGTTACTTTTTGTTAAATTTACTTTTCTTCTTTCACTTCTTACCTGTCAATGTTATTAATATTTTTAGGAACAATAAATCACATTAATTCCTTATCTCATGTGAAATTTCATATTTATGATTGATACCTTTAAATGTCATTTGTTGAAGGAAGATTATTCATTTTTTCATTCAATAAATATTTTTTAGAATAATAAGTCCCAGGCACAAGACCAGTATTATGTTCTAGGCATTGGGGATACCATGTTCACAAGACAGACTATGATTTACAGGATCAGATGTGGACTCTCAAATTCGACTGAGAATAAAACAGACACAAACAAGTAAATAAAGTTAATTTCAAGTTGTAATTGATGCTATCCCAGGCACAAGACCAGTATTATGTTCTAGGCATTGGGGATACCATTACCTGTCAATGTTATTAATATTTTTAGGAACAATAAATCACATTAATTCCAACATGCAAAGAGGAAATCTCC
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Genome annotation Genes: Genetic variation: Sequence conservation
Coding, noncoding, miRNA, etc. Isoforms Expression ~3 billion bp ACAATAAATCACATTAATTCCTTATCTCATGTGAAATTTCATATTTATGATTGATACCTTTAAATGTCATTTGTTGAAGGAAGATTATTCATTTTTTCATTCAATAAATATTTTTTAGAATAATAAGTCCCAGGCACAAGACCAGTATTATGTTCTAGGCATTGGGGATACCATGTTCACAAGACAGACTATGATTTACAGGATCAGATGTGGACTCTCAAATTCGACTGAGAATAAAACAGACACTAAACAAGTAAATAAAGTTAATTTCAAGTTGTAATTGATGCTAGAAAGACAATGAAACAGAGCCATGTGACCAATGAGAGAGATGAGGGTGGCAGCAGCCTGTTTTAGATAAGGTACCTGATTGGTGGGATTGGAAGACCTCTCTGAGATTAGTGTCTTCAGATATGCCTTAATGATATGAAAGAACCATTCATGGGAAGGCCTAGCATTAAAAACCGTCTAGGCAGAATGAGCAGCAAGTGCAAGGGTCCTGGATAGGAATGAGCTGGATATACTCAAGGAAGAAAGAGAAACTATGGAAAAATGAAAATAGATTTTAAAACATGTTAATTCACGTTACTTTTTGTTAAATTTACTTTTCTTCTTTCACTTCTTACCTGTCAATGTTATTAATATTTTTAGGAACAATAAATCACATTAATTCCTTATCTCATGTGAAATTTCATATTTATGATTGATACCTTTAAATGTCATTTGTTGAAGGAAGATTATTCATTTTTTCATTCAATAAATATTTTTTAGAATAATAAGTCCCAGGCACAAGACCAGTATTATGTTCTAGGCATTGGGGATACCATGTTCACAAGACAGACTATGATTTACAGGATCAGATGTGGACTCTCAAATTCGACTGAGAATAAAACAGACACTAAACAAGTAAATAAAGTTAATTTCAAGTTGTAATTGATGCTACTATGGAAAAATGAAAATAGATTTTAAAACATGTTAATTCACGTTACTTTTTGTTAAATTTACTTTTCTTCTTTCACTTCTTACCTGTCAATGTTATTAATATTTTTAGGAACAATAAATCACATTAATTCCTTATCTCATGTGAAATTTCATATTTATGATTGATACCTTTAAATGTCATTTGTTGAAGGAAGATTATTCATTTTTTCATTCAATAAATATTTTTTAGAATAATAAGTCCCAGGCACAAGACCAGTATTATGTTCTAGGCATTGGGGATACCATGTTCACAAGACAGACTATGATTTACAGGATCAGATGTGGACTCTCAAATTCGACTGAGAATAAAACAGACACAAACAAGTAAATAAAGTTAATTTCAAGTTGTAATTGATGCTATCCCAGGCACAAGACCA…. Genetic variation: SNPs and CNVs Sequence conservation Regulatory sequences: Promoters Enhancers Insulators Epigenetics: DNA methylation Chromatin
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Density of biological information in the human genome
Chr5: 133,876,119 – 134,876,119 Genes Transcription TF binding Histone mods Mouse orthology SNPs Repeats
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Annotation depth varies by species
Human, Mouse (Fly, Worm, Yeast): Chromosome assemblies Dense gene and regulatory maps, variation, etc. Other models (Dog, Chicken, Zebrafish): Chromosome assemblies Partial gene maps; variation; little regulatory data Low coverage vertebrate genomes: Scaffold assemblies Few annotated genes Used for comparative purposes
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Portals to access and interpret genomes
UCSC Genome Browser (genome.ucsc.edu): Visualization, data recovery, simple analysis (also ENSEMBL (ensembl.org): Visualization, data recovery, simple analysis Integrative Genomics Viewer (broadinstitute.orgsoftware/igv/): Local genome viewer (visualize local and remote data) Galaxy (main.g2.bx.psu.edu): Complex data analysis and workflows
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UCSC Genome Browser genome.ucsc.edu Wiki Page: genomewiki.ucsc.edu
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Read the User Guide
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Human genome main page (Feb 2009 assembly)
There are multiple assemblies for many genomes! Different genome assemblies have different coordinate systems and may have different annotations: chr2:236,438, ,438,948 in March 2006 (hg18) is chr2:236,773, ,774,209 in Feb 2009 (hg19)
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Categories of data: displayed as tracks
Genome Viewer Categories of data: displayed as tracks Discrete intervals (genes) or continuous (transcription) Category: Genes and Gene Prediction Hyperlinks and tabs for individual tracks Go to track description page Hide or show data in genome viewer Some tracks include multiple datasets (‘subtracks’) Go to track description page to select Different assemblies have different annotations!
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Sample Genome Viewer image: PITX1
Base position Gene model (discrete) Transcription (continuous) TF binding SNPs Repeats
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Which gene annotation to use?
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Gene description page and links to other resources
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‘Layered’ tracks: Transcription
Display options Subtracks
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Integrating different types of annotation data
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Integrating different types of annotation data
Proximal enhancer Promoter
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Common Genome Browser file formats
BED format For interval data (e.g., exons) Tab-delimited format: chr start stop identifier BED coordinates are ‘zero-based, half-open’: the start position is 0-based, the end position is 1-based Position coordinates on the browser are 1-based. This leads to confusion if you are not careful. chr is shown in the browser as chr16: BEDTools: utilities for comparing genomic features you will use on your problem sets WIG format For continuous data (e.g., the Transcriptome track mentioned earlier) WIG files are very large! BigWig is an alternative format you will learn about in discussion.
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The Table Browser (under Tools) Select datasets Compare datasets
Download data
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Integrating your own experimental data
Proximal enhancer Promoter Mapping binding sites for a transcription factor of interest
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Custom tracks and sessions
Display and share your own data on the browser Custom tracks can be intersected, etc. in the Table Browser
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Track Hubs (under My Data)
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Integrating Track Hub data with your own experimental data
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Genome Browser utilities: BLAT
(under Tools) Rapidly find sequence locations in an assembly DNA sequences >24 bp and 95% identical to target genome
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Assembly quality and annotation vary across genomes
Assembly not anchored to chromosomes Poor gene annotation Assembly quality metrics Whole-genome alignment to mouse
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Genome Browser utilities: LiftOver
(under Tools) Convert coordinates from one assembly to another (e.g., hg18 to hg19) Identify orthologous positions between genomes (e.g., human to mouse)
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Galaxy main.g2.bx.psu.edu
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Wrap-up Problem Set #1: Learn how access and manipulate genomic datasets Next lecture: High-throughput sequencing technologies
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