The TA vector contains single 3’
-
dU overhan
gs that are compatible with direct
ligation of the PCR product without the need for intermediate reactions. Following
transformation, the dU residues are replaced with dT residues as the bacteria replicate the
plasmid. The ease of such a technique was the
reason behind choosing pCR II TOPO TA
cloning vector. In addition, pCR II TOPO TA vector contains ampicillin resistance
marker which permits only transformed bacterial cells to grow in ampicillin containing
media, this strategy used for cloning.