Very big implications: Life in a cauldron
The solution to the mystery came from a close examination of the genes. The core genes common to E. coli K12 and O157:H7 are virtually identical. The remaining genes are a different story. They include many of unknown origin and many that appear to be parts of derelict bacterial viruses. There seems to be rapid exchange of genes amongst even distant bacteria, partially mediated by viruses. Bacteria live in a frothing genetic soup.

While many of the foreign genes have not been identified, some appear to be related to pathogenesis. A detailed study of the genes in the foreign regions of the O157 genome may yield a deeper knowledge of how pathogenesis occurs. A detailed study of the surrounding DNA may shed light on how pathogens arise in evolution.

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