The procedure of sonication based 4C-Seq. A) The scheme of 4C-Seq process to generate high-throughput sequencing data for analysis. Two rounds of PCR reactions (nested PCR) were used to amplify bait interacting regions (primers shown in arrows). The fragmented DNA pieces for sequencing can be classified in four categories shown in the left panel. B) DNA electrophoresis gel images of constructed 4C library from nested PCR. C) DNA electrophoresis gel images of 4C library after fragmentation for NGS.