Why did I obtain more than one PCR band after transformation?

I did a ligation of a 120pb fragment digested by EcoR1 and NdeI in the Pt7-7 digested plasmid (Overnight at 16ºC), then I transformed DH5a competent cells and after 18 hours at 37ºC I found 3...

25 May 2014 289 5 View