Physical map of the E. coli genome
This map was obtained from sequencing DNA and plotting gene positions. Key to components from the outside in:

  • The DNA replication origin and terminus are marked.

  • The two scales are in DNA base pairs and in minutes.

  • The orange and yellow histograms show the distribution of genes on the two different DNA strands.

  • The arrows represent genes for rRNA (red) and tRNA (green).

  • The central “starburst” is a histogram of each gene with lines of length that reflect predicted level of transcription.

    • [F. R. Blattner et al., “The Complete Genome Sequence of Escherichia coli K-12” Science 277, 1997, 1453–1462. DOI: 10.1126/science.277.5331.1453. Reprinted with permission from AAAS. Image courtesy of Dr. Guy Plunkett III.]