Widespread protein sequence similarities: origins of Escherichia coli genes

Systematic surveying of sequence similarities among amino acid sequences encoded by Escherichia coli K-12 genes obtained from SwissProt database using FASTA algorithm helps understand the evolutionary origins of E. coli genes. Evolution of E. coli genes involves significant duplication and divergence of ancestral genes. Absence of coherent pattern of favored separations in map distances between genes of sequence-related proteins suggests the absence of genome doubling in the past.