Daisy chaining DNA

Daisy chaining DNA is the process of when DNA undergoing PCR amplification becomes tangled and forms a 'daisy chain.' During PCR, primers or dNTP's will eventually be used up and limit further reactions; it is when the primers deplete that causes daisy chaining. Since the denaturing and annealing processes still continue without primers, the single-stranded DNA molecules reanneal to themselves. However, this reannealing does not always occur to another complementary strand. It is this imperfect match up that causes 'tangles'. These tangles look like a daisy chain.