The Smaller Band May Be A Single-Stranded Form Of The PCR Product. The Occurrence Of It Could Be Due To That Elongation Of The PCR Product Is Not Complete Or That PCR Product Is Denatured During The Preparation. In This Case, To Re-Anneal The Single-Stranded DNA By Incubating The Solution At 95˚C For 2 Minutes And Let It Cool Slowly To Room Temperature. The Re-Annealed PCR Product Can Be Used As Usual In All Downstream Applications.