Integrative Genomics Viewer
Rockefeller University, Bioinformatics Resource Centre
https://rockefelleruniversity.github.io/IGV_course/
IGV
Overview
- Introduction to IGV.
- What is IGV.
- How to run IGV.
- Navigating IGV.
- The IGV user interface.
- Moving around genomes.
- Loading and visualising data.
- Genome information and annotation.
- User supplied data.
- Sample information.
- External data.
- Displaying genomics data
- Basic visualisation.
- Data dependent visualisation.
What is IGV?
- Created by the Broad institute.
- Genome browser.
- Visualises genomic data (expression, ChIP, resequencing, multiple alignment, shRNA).
- Handles most common genomic data types.
- Java Desktop application
- No dependence on server.
- Loads data locally or from URL, consumes memory and CPU.
How to run IGV?
- Requires Java
- IGV available from Broad
How to run IGV? (Binary)
- Download to computer.
- Runs locally.
- Archived versions available.
How to run IGV? (Webstart)
- Runs from webstart.
- Always runs latest version of IGV.
IGV GUI
IGV GUI
- Sample information panel <1>
- Genome Navigation panel <2>
- Data panel <3>
- Attribute panel <4>
Menu bar
- File - Load data/sample information.
- Genomes - Load and manage genomes.
- View - Display preferences.
- Tracks - Group/sort/filter data tracks.
- Regions - Create region/gene lists.
- Tools - Access to Integrated tools (IGVtools/Bedtools).
Moving around genomes
- Cytoband selection and zooming
- Scrolling
- Selection of region of interest
Moving around genomes
Zoom
Scrolling
Jump to region
“Bookmarking” regions of interest
Regions may be added to “Regions of interest”.
These act as bookmarks for areas of particular interest.
Bookmarks can be added by:
- Bookmarking visible window.
- Selecting region within window.
Bookmarking - Visible window
Bookmarking
Bookmarking
- Bookmarks may be created quickly by selecting “region of interest” button.
- Once selected just point-and-click where you want each edge to be.
Sequences from regions of interest
- A useful feature of “regions of interest” is to retrieve the sequence.
- You can even directly BLAT sequences.
Sequences from regions of interest
- BLAT results present as table of hits.
Viewing sequences
- At a predefined resolution, sequence information becomes available.
Viewing sequences
- Strand of sequence can be altered.
- Differing translation tables can be selected.
Gene Lists
- When you do not have a region of interest but a group of genes you can use Gene Lists (“Regions” > “Gene Lists”).
- You create your own list or use one of the curated lists.
Gene Lists
Using gene lists you can visualise several genes concurrently.
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Loading data in IGV
Loading Genome Information
- Most genomes can be selected from dropdown.
Loading Genome Information
- Genomes not included may be downloaded from repository
Loading Genome Information
- For supported genomes, gene positions are automatically included in “feature” panel.
- Additional gene positions can be loaded into IGV in gff format
Loading Sample data
- Most common formats can be loaded into IGV through file menu
- Acceptable data formats include:-
- BED (.bed)
- BAM and index (.bam with .bai/.bam.bai)
- BigWig (.bw)
- BedGraph/Wig (.bedGraph, .wig)
- And many more…
- For a full list of compatible file formats check out the IGV website
Loading Sample Metadata
- IGV allows the inclusion of information on samples.
- Sample information is included in sample information panel. ]
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Loading Sample Metadata
Example Sample information file http://www.broadinstitute.org/igvdata/exampleFiles/exampleSampleInfo.txt
Sample Metadata with TrackTables
- Tracktables is a R/Bioconductor package.
- Creates HTML reports with sample information for use with IGV.
Using sample information
Sample information can include discrete and continuous.
Can be used to “sort” and “filter” tracks.
Can split tracks across panels by “group”
Loading Genome Information
Loading external data and annotation
** Load data from a URL ** - As with UCSC, IGV supports data hosted on external servers. - Data accessible from a URL such as HTTP and FTP can be loaded using “File” > “Load from URL”.
Load data from a URL
Try: “https://github.com/ThomasCarroll/tracktables-Data/raw/master/H3K4me3_Example.bw”
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Loading external data and annotation
** Load data from a server (IGV/Encode servers)**
Unlike UCSC, IGV comes with few external tracks.
External tracks (relevant to the genome) can be loaded from the IGV server or Encode-IGV server.
Load data from a server (IGV/Encode)
Grabbing encode data directly
- Encode data can be downloaded from UCSC.
- This however does not come with sample information provided through IGV interface.
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Viewing Data
Viewing data
IGV associates common file formats with default display methods.
Most of the time IGV will make a sensible choice how we wish to display data.
Accepted formats and default display.
- Information on accepted file formats and default display can be found at:
http://www.broadinstitute.org/software/igv/RecommendedFileFormats
Bed/bigBed
- Basic
- Tab-delimited
- Chrom,Start,End
- Bed6
- bigBed (recommended)
Wig, BedGraph and BigWig
- Wig/bedGraph require high memory load.
- Recommended format is bigWig.
BAM alignment files
- BAM files contain alignment information.
- Require an accompanying .bai index file for display.
Finer control of display
IGV allows for customization of track display.
“View” > “Preferences”
Select track (right click)
Display preferences
** General **
Display preferences
** Tracks **
Display preferences
** Alignments **
Track display options
** Graph/interval files** - Track colour/appearance
Track display options
** Graph/interval files** - Graph type
Track display options
Data Scaling
Track display options
Autoscaling adjusts to track’s visible signal maximum.
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Some more useful IGV features
IGV displays splicing
IGV - Overlay tracks
Overlay tracks
Track summarisation
IGV can be used to combine tracks
Sum of two tracks
Create new summed track
There are also options for subtract, divide and multiply.
IGVtools
- IGVTools can be used to post-process genomics data.
- Includes indexing, sorting and genome graph creation.
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Saving images of tracks
- “File” > “Save Image”
- You can easily save images from IGV to vector based svg format. This means you can further customize your tracks and assemble them into figures using Inkscape or Illustrator.
Saving your session
- If you want to revisit your tracks at a later date, you can save the entire session.
- When you restart later on you just have to reopen the session and you will be right back where you were.
- “File” > “Save Session”