Experimental evolution of an Escherichia coli line lacking ribonucleotide reduction.. Escherichia coli B strain:B

We created a line of Escherichia coli that lacks ribonucleotide reduction and evolved this line under conditions where deoxyribonucleoside access in growth media was limited. The primary goal was to understand the steps by which obligate intracellular bacteria that have lost of ribonucleotide reduction have adapted to this state. We sequenced the genomes of the ancestral knockout line, the wild-type line it derives from, and evolved knockout and wild-type control lines grown under conditions where availability of deoxyribonucleosides required for growth was reduced. We identified mutations in our knockout lines to genes that are also mutated in obligate intracellular symbionts and pathogens that lack ribonucleotide reductase genes.