Use high-efficiency competent cells (≥1 × 108cfu/μg DNA) for transformations. Ligation of fragments with a singlebase
overhang can be inefficient, so it is essential to use cells with a transformation efficiency of 1 × 108cfu/μg DNA (or
higher) in order to obtain a reasonable number of colonies. We recommend using JM109 High Efficiency Competent
Cells (Cat.# L2001); these cells are provided with the pGEM®-T and pGEM®-T Easy Vector Systems II. Other host
strains may be used, but they should be compatible with blue/white color screening and standard ampicillin selection.