Figure 3From: The impact of horizontal gene transfer in shaping operons and protein interaction networks – direct evidence of preferential attachmentNumber of E. coli genes in the genome organizations: (A) operons, (B) protein interaction network (PIN). Genes are classified into three evolutionary categories Core, Non-core and HGT genes. Core genes predominantly occur in both operons and protein interaction networks (P-value < 0.001).Back to article page