Biology Reference
In-Depth Information
Fig. 2.
Differential image analysis of two groups of gels with the Melanie package.
Each group has 3 replicate gels. The left column shows three control gels, and the
right column shows the corresponding regions on three treated gels. The three-
dimensional (3-D) window (bottom right) highlights two neighboring spots present
in the control sample, but absent from the drug-treated sample.
Matching gel images is another critical process, whether based on
the previous detection of spots
4
or on the intensities of the regions
before the detection of spots.
5
Gel matching involves the comparison
of the spatial distribution of spots of a gel image taken as a reference
image (e.g. control) with a second gel image (e.g. disease). Expectable
variations induced by gel running conditions and gel scanning should
not interfere with the assessment of changes in protein expression.
Needless to say, the subsequent steps on gel image analysis will be erro-
neous if spots representing the same protein are not correctly matched
or if spots representing different proteins are mistakenly matched
together. To minimize this risk, some tools propose the initialization of
