FAQ: Why do I see two peaks (one large and one small) overlapping in one position of the electropherogram?

This phenomenon may be explained by one of the two following possibilities. The first is more than one size of PCR product was amplified.  If the amplification does not produce a homogeneous product and more than one species is amplified with sequence similarity to another, both can be sequenced with the added sequencing primers. Another explanation may be that unprocessed sample remained on the side of the reaction tube, leading to aberrant reads. Please be sure to vortex and quickly spin the reaction tube after treatment with the Exo-CIP reagents.