Weighted scatter-plot of the pattern of detected tandem repeat length variation. Length of repeat unit is plotted against the absolute difference between query and hit repeat block lengths. One variant corresponding to a length difference of 144 for a 48-nucleotide repeat has been omitted. Note that the length of repeat unit, rather than the tandem repeat array length, is plotted on the x-axis and most observed length differences are multiples of the corresponding unit length. The area of each circle is proportional to number of variants observed with a given unit length, and a given nucleotide difference between the representative and variant sequences.