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What technologies does JBrowse 2 use#

  • React
  • mobx-state-tree
  • web-workers
  • Typescript
  • Electron (for desktop specifically)

What is special about JBrowse 2#

One thing that makes JBrowse 2 special is that we can create new view types via our plugin system, e.g. circular, dotplot, etc. Anything you want can be added as a view, and can be shown alongside our other views

This makes JBrowse 2 more than just a genome browser-- it is really a platform that can be built on.

What are new features in JBrowse 2#

  • Uses web workers for multi-core data parsing and rendering of tracks
  • Use ctrl+scroll to zoom in and out quickly
  • Status updates while track is loading (e.g. Downloading BAM index...)
  • Hi-C visualization from .hic format files
  • Can display multiple chromosomes or discontinuous regions on a single linear genome view
  • Can connect to UCSC trackhubs
  • Alignments track has both coverage and pileup display integrated in a single track
  • Read pileups can be sorted by various attributes
  • Has ability to show soft clipped bases on reads
  • Interactively edit the configuration using the GUI
  • Circular, dotplot, stacked synteny views
  • SV inspector, that gives tabular and circular overview of data in a single view
  • Linear genome view can be reverse complemented

Can the linear genome view be reverse complemented#

Yes! See here


What web server do I need to run JBrowse 2#

JBrowse 2 by itself is just a set of JS, CSS, and HTML files that can be statically hosted on a webserver without any backend services running.

Therefore, running JBrowse 2 generally involves just copying the JBrowse 2 folder to your web server html folder e.g. /var/www/html/.

If you use a different platform such as Django, you may want to put it in the static resources folder.

Note that the server that you use should support byte-range requests (e.g. the Range HTTP header so that JBrowse can get small slices of large binary data files.

BAM files do not work on my server#

If you are using Apache then you will probably want to disable mime_magic. If mime_magic is enabled, you may see that your server responds with the HTTP header Content-Encoding: gzip which JBrowse does NOT want, because this instructs the browser to unzip the data but JBrowse should be in charge of this.

How can I start the JBrowse 2 app as a developer#

We recommend that you have the following

Then you can follow steps from our README

It basically boils down to git cloning our repo, and running yarn start which creates a development server on port 3000

You can use PORT=8080 yarn start to manually specify a different port

Note that this is a development server that gets started up. To install jbrowse 2 in production on your webserver, see below

Do you have any tips for learning React and mobx-state-tree#

Here is a short guide to React and mobx-state-tree that could help get you oriented

How can I setup JBrowse 2 in production#

We recommend following the steps in the quickstart web guide.

The general procedure is using the jbrowse create /var/www/html/jb2 and this will download the latest version of jbrowse to your web folder e.g. in /var/www/html

You can also use jbrowse upgrade /var/www/html/jb2 to get the latest version

How can I setup JBrowse 2 without the CLI tools#

The jbrowse CLI tools are basically a convenience, and are not strictly required

Simple tasks can be done without it

For example, for jbrowse create, you can visit the blog and download the latest jbrowse-web release tag, and unzip it into your web directory

For other things, like add-assembly and add-track, you can manually edit the config.json, reviewing the config docs and sample configs will be valuable

Understanding the config basics will come in handy also because you can manually edit in advanced configs after your tracks are loaded however be careful because corrupt configs can produce hard to understand errors, because our config system is strongly typed

Feel free to message the team if you encounter these

How do I load a track into JBrowse 2#

If you have followed the above steps and installed jbrowse 2 on your webserver and loaded the assembly, and have the CLI tools installed

jbrowse add-track -a hg19

This will setup a bigwig track on the hg19 assembly in your config.json. Make sure to run the command inside your current jbrowse2 folder e.g. /var/www/html/jbrowse2 or wherever you are currently setting up a config.json (you can have multiple configs)

Note that you can also use remote URLs

jbrowse add-track http://yourremote/myfile.bam

The add-track command will do as much as possible to infer from the file extension how to configure this track, and automatically infer the index to be myfile.bam.bai


Why do all the tracks need an assembly specified#

We require that all tracks have a specific genome assembly specified in their config. This is because jbrowse 2 is a multi-genome-assembly browser (and can compare genomes given the data). This may be different to using say jbrowse 1 where it knows which genome assembly you are working with at any given time

How are the menus structured in the app#

In JBrowse 1, the app level menu operated on the single linear genome view, but with JBrowse 2, the top level menu only performs global operations and the linear genome view has it's own hamburger menu. Note that each track also has it's own track level menu.

Why do some of my reads not display soft clipping#

Some reads, such as secondary reads, do not have a SEQ field on their records, so they will not display softclipping.

The soft clipping indicators on these reads will appear black.