Home FAQs Why do I see two peaks (one large and one small) overlapping at a single position in the electropherogram after using the Exo-CIP Rapid PCR Cleanup Mix (NEB #M1058)?

FAQ: Why do I see two peaks (one large and one small) overlapping at a single position in the electropherogram after using the Exo-CIP Rapid PCR Cleanup Mix (NEB #M1058)?

This is commonly explained by one of two issues: (1) more than one PCR product was amplified. If amplification yields a mixed population and the products share sequence similarity, both may be sequenced by the added primer(s), producing overlapping peaks; or (2) the untreated sample remains on the side of the reaction tube and later mixed into the reaction, leading to aberrant reads. After adding Exo-CIP mix, mix the reaction thoroughly and briefly spin down to collect all liquid.