Fig. 2

a Amplification of the 500 bp upstream and downstream DNA fragments of hasS. Lane 1, 400 ng DNA ladder; lane 2, 3 μl of the 500 bp PCR product of the upstream genomic DNA sequence of hasS; lane 3, 3 μl of the 500 bp PCR product of the downstream genomic DNA sequence of hasS. b Colony PCR of fused deletion alleles. The 500 bp upstream DNA fragment and the 500 bp downstream DNA fragment were fused and cloned into the pEX18Tc vector via Gibson assembly. Lane 1, 400 ng, 100 bp DNA ladder; lane 2–6, 10 μl of PCR products of five colonies randomly selected, which all showed the 1 kbp fused deletion alleles