Mashome - Genome Browser Mashup library
Matt Rasmussen 2012
http://mattrasmus.com/mashome
rasmus@alum.mit.edu

  
This library allows one to visualize *very* custom genome browser
tracks within a host genome browser web page (e.g. UCSC, Ensembl,
generic).  Custom tracks are are built and controlled using
javascript.  Data displayed within tracks can be fetched using AJAX.


Purpose:

The purpose of this library is to provide a way to inject your own
HTML elements into a web-based genome browser.  Mashome provides a
simple interface for responding to view changes (moving and zooming
along the chromosome) so that only a minimal amount of extra code is
needed to create a custom track.  This library should be used in cases
where a typical track (BED file, WIG file, etc) is not suitable for
the information you wish to plot.  In general, one should be able to
visually align any arbitrary plot next to a native genome browser
track and use the existing genome browser's UI to navigate both the
genome and one's plot.


Examples of very custom tracks:

1. Plot a heatmap matrix aligned with native tracks.  If the columns
   of the heatmap correspond to coordinates along the genome, then one
   can easily compare values in the heatmap with other genomic
   elements/values being displayed in native tracks.

2. Display additional text information.  By registering callback
   functions for mouse clicks and view changes, one can make a "track"
   that displays extra text information (e.g. detailed information
   about a gene/element or links to additional resources).

3. Arbitrary/flexible plotting.  Using HTML5's canvas element, one can
   create new types of plots that cannot be represented in existing track
   formats (BED, WIG, etc).  For example, by listening to clicks on genomics
   elements, one could plot a local genealogy or gene family.


How it works:

1. First, a bookmarklet is used to inject into a web-based genome browser
   (e.g. UCSC genome browser) the Mashome HTML element directly below
   the "native" tracks.  This element will contain your own *very*
   custom tracks.

2. The Mashome interface includes a text input labeled "tracks URL:".  Simply
   enter the URL of a javascript file hosted anywhere on the Internet and it
   will be loaded by Mashome.  This javascript file should contain calls to
   the mashome library that add custom tracks to the browser.

3. Custom tracks can be additional UI elements, extra text displays,
   or dynamic graphical plots created by HTML5's canvas element.  The
   data to display can be fetched by any mechanism the user chooses.
   For example, AJAX calls could be used to fetch data from a
   third-party web server or even from the localhost.

A simple example using a generic stub genome browser can be seen here:

  http://mattrasmus.com/mashome/pub/mashome/genome-browser