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DiffLogo.com provides an easy-to-use web-frontend for the R package DiffLogo (also available at Bioconductor).

This website allows researchers without any technical background to investigate and to compare sequence motifs from DNA, RNA, or proteins. The user is allowed to upload an unlimited amount of motifs and to compare up to 10 of them. Each motif is represented by a motif file. DiffLogo.com supports three different file formates described here.

DiffLogo.com calculates Sequence Logos directly after a file was uploaded and validated. The user is allowed to select two files for creating a single difference logo or to select more than two files for creating a DiffLogoTable. The resulting files can be easily downloaded via a web link.

Results

Difference logo

If the user has selected only two motifs then diffLogo.com will create one single difference logo. A difference logo illustrates the differences between two motifs such as binding motifs of transcription factors from different species. It displays position-specific differences of symbol distributions by a stack of symbols. The stack height is proportional to the difference of the symbol distributions quantified by the Jensen-Shannon divergence. The Jensen-Shannon divergence is zero in the case of two identical base distributions and 1 in the case of two maximally different base distributions. Symbols overrepresented in the first motif and underrepresented in the second motif are plotted upward. Respectively, symbols underrepresented in the first motif and overrepresented in the second motif are plotted downward.

DiffLogoTable

If the user has selected more than two motifs then diffLogo.com will create a DiffLogoTable that contains all pair-wise comparisons of the input motifs. Similar motifs are placed in nearby rows and columns. The degree of the similarity between two motifs is depicted by the background color from green (similar) to red (dissimilar). The sequence logos of the input motifs are shown at the top of the table.