Some of the sequence file formats such as *.seq list several base number pairs before the sequence. Each pair corresponds to a gene contained in the sequence with the first number identifying the base that the gene starts at and the second number the base the gene ends at. When a W-curve is rendered the parts of the curve that correspond to the genes should be one color, so they can be easily discerned from the rest of the sequence. The text listing of the sequence should also have the genes highlighted.