acedb-other-dotter

visualisation of sequence similarity

For the analysis of biological sequences, a general principle is to compare corresponding regions between related proteins, RNA or DNA. Dotter, as an interactive dotplot with varying thresholds, displays graphically the similarity of DNA or protein sequence to itself or another sequence.

dotter

detailed comparison of two genomic sequences

Dotter is a graphical dot-matrix program for detailed comparison of two sequences. * Every residue in one sequence is compared to every residue in the other, and a matrix of scores is calculated. * One sequence is plotted on the x-axis and the other on the y-axis. * Noise is filtered out so that alignments appear as diagonal lines. * Pairwise scores are averaged over a sliding window to make the score matrix more intelligible. * The averaged score matrix forms a three-dimensional landscape, with the two sequences in two dimensions and the height of the peaks in the third. This landscape is projected onto two dimensions using a grey-scale image - the darker grey of a peak, the higher the score is. * The contrast and threshold of the grey-scale image can be adjusted interactively, without having to recalculate the score matrix. * An Alignment Tool is provided to examine the sequence alignment that the grey-scale image represents. * Known high-scoring pairs can be loaded from a GFF file and overlaid onto the plot. * Gene models can be loaded from GFF and displayed alongside the relevant axis. * Compare a sequence against itself to find internal repeats. * Find overlaps between multiple sequences by making a dot-plot of all sequences versus themselves. * Run Dotter in batch mode to create large, time-consuming dot-plots as a background process.