Dye Blobs

The presence of unincorporated fluorescently labeled dideoxyterminators in the sequence results (Figure 1) is due to their insufficient removal in the dye removal method. The resulting dye blobs, so called for their blob appearance on the array image, will interfere with the analysis of the sequence. Strong dye blobs can cause the loss of the first 60 - 120 bases of the sequence.

Figure 1. Chromatogram displaying large peaks unincorporated dideoxyterminators.

Small amounts of unincorporated dideoxyterminators do sometimes carry though the removal procedure. The majority of sequence data is unaffected. Base calling by analysis software ignores the small amount of signal associated with the dye blob. A small dye blob is illustrated at ~120 base region of the chromatogram in Figure 2. As in both figures, small dye blobs can affect base calls but the data can usually be manually edited. Contact core staff if you are experiencing issues with dye blobs.

Figure 2. Chromatogram with small dye blob obscuring bases 121.