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Computational tools and Interoperability in Comparative ... - CBS

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GeneWiz browser<br />

nearly <strong>in</strong>stantly when requested by the user, by<br />

redraw<strong>in</strong>g all the components like tracks, legends,<br />

marks <strong>and</strong> text for every view. This allows the<br />

browser to scale the plot to make use of the entire<br />

plott<strong>in</strong>g area, by not rescal<strong>in</strong>g all parts of the plot<br />

equally. For example, zoom<strong>in</strong>g 10 x will stretch a<br />

data lane 10 <strong>in</strong> genome position axis, however<br />

the lane height <strong>and</strong> distance to the neighbor lane<br />

will rema<strong>in</strong> constant. The dynamic nature of the<br />

GeneWiz browser requires pre-­‐b<strong>in</strong>n<strong>in</strong>g of data for<br />

each zoom level, all of which are stored on a cen-­‐<br />

tral server; for improved efficiency only data re-­‐<br />

quested by the user are sent. The approach to<br />

store per-­‐nucleotide <strong>in</strong>formation as table records<br />

<strong>in</strong> a database (e.g. MySQL) has proved unfeasible,<br />

as the number of records per genome exceeds<br />

millions, <strong>and</strong> the construction of <strong>in</strong>dexes would be<br />

very time consum<strong>in</strong>g. Instead, a memory mapp<strong>in</strong>g<br />

technique was chosen, that allows the server to<br />

directly obta<strong>in</strong> the values from b<strong>in</strong>ary files when<br />

provided with the zoom w<strong>in</strong>dow <strong>and</strong> level, for any<br />

chromosome <strong>in</strong> the database. (Examples are pro-­‐<br />

vided as supplemental data, http://www.cbs.-­‐<br />

dtu.dk/services/gwBrowser/suppl/).<br />

The client is written as a JavaApplet, that obta<strong>in</strong>s<br />

the data remotely from the server<br />

(http://ws.cbs.dtu.dk/cgi-­‐b<strong>in</strong>/gwBrowser-­‐<br />

0.91/server.cgi). The browser server is written <strong>in</strong><br />

Perl/CGI, while a compiled c-­‐program h<strong>and</strong>les the<br />

access to the b<strong>in</strong>ary data files. The options cur-­‐<br />

rently supported are listed <strong>in</strong> Table 2.<br />

Table 2 GeneWiz Browser server options.<br />

Option description<br />

d The unique identifier for the atlas<br />

Feature type (e.g. CDS,rRNA,tRNA) when return<strong>in</strong>g<br />

ft<br />

annotations<br />

f Data field to return<br />

b Beg<strong>in</strong> of w<strong>in</strong>dow<br />

e End of w<strong>in</strong>dow<br />

l Zoom level<br />

z Enable zlib compression of output<br />

m=i Return the genome length<br />

m=avg/stddev/m<strong>in</strong>/max Return aggregate data for w<strong>in</strong>dow/genome<br />

m=d<br />

Return data values provided field, w<strong>in</strong>dow <strong>and</strong> zoom<br />

level<br />

m=c Return colors provided two or three-step ranges<br />

m=n Return nucleotides provided the w<strong>in</strong>dow<br />

m=a Return annotations (used together with option ‘ft’)<br />

<strong>and</strong> genes as well as numerical data associated<br />

These options (Table 2) can be <strong>in</strong>corporated <strong>in</strong>to a with each nucleotide. The disproportional capabil-­‐<br />

s<strong>in</strong>gle URL. For example, one could request all ity of the GeneWiz browser implies that all com-­‐<br />

ponents (legends, tracks, marks, etc.) are regene-­‐<br />

<br />

m-­‐ rated for every view requested by the user. Figure 4<br />

http://ws.cbs.dtu.dk/cgi-­‐<br />

outl<strong>in</strong>es the GeneWiz browser workflow.<br />

b<strong>in</strong>/gwBrowser-­‐<br />

-­‐<br />

When submitt<strong>in</strong>g a job via the web <strong>in</strong>terface, the<br />

<br />

request is assigned a job identifier, under which<br />

<br />

a-­‐<br />

all data lanes <strong>and</strong> configurations are kept. After<br />

tions are described <strong>in</strong> the xml record, which can<br />

the job has been processed the user may alter lane<br />

be downloaded from the web<br />

order, colors, ranges, <strong>and</strong> append various types of<br />

(http://ws.cbs.dtu.dk/cgi-­‐b<strong>in</strong>/gwBrowser-­‐<br />

marks to the plot. The layout of a given browser<br />

0.91/fetchxml.cgi?AL111168GENOMEatlas). Fur-­‐<br />

<strong>in</strong>stance is governed by an XML file, located on the<br />

ther examples are provided <strong>in</strong> the supplemental<br />

server. When generat<strong>in</strong>g the graphical representa-­‐<br />

data section.<br />

tion of the genome, the client Java program will<br />

make requests to the server to acquire aggregated<br />

The GeneWiz workflow <strong>and</strong> data displayed<br />

values, such as the averages, st<strong>and</strong>ard deviations,<br />

The GeneWiz browser plots <strong>and</strong> provides dispro-­‐<br />

m<strong>in</strong>ima, <strong>and</strong> maxima as well as lane data <strong>and</strong> an-­‐<br />

portional zoom<strong>in</strong>g for data perta<strong>in</strong><strong>in</strong>g to features<br />

notations.<br />

208 St<strong>and</strong>ards <strong>in</strong> Genomic Sciences

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