Genome Size

Value 4.6e+6 Base pairs
Organism Bacteria Escherichia coli
Reference Blattner FR et al, The complete genome sequence of Escherichia coli K-12. Science. 1997 Sep 5 277(5331):1453-74. p.1454 right column 4th paragraphPubMed ID9278503
Method P.1453 middle columnbottom paragraph: "Sequencing was carried out in sections, with steadily improving technical approaches. The M13 Janus shotgun strategy proved to be the most efficient strategy for data collection and closure. It involved initial random sequencing at a four- to fivefold redundancy in the Janus vector (ref 13 Burland et al 1993, PMID 8346017), followed by computerized selection of templates to be resequenced from the opposite end, followed by limited primer walking."
Comments P.1454 right column 4th paragraph: "The genome of E. coli K-12 consists of 4,639,221 bp of circular duplex DNA [i.e., a single chromosome](note (30)." Note 30: "The zero reference (0/100, formerly 0/60) of the map was originally defined as the position of the first marker (thr) transferred by E. coli Hfr H, which was used in genetic mapping by interrupted mating, and a convention has arisen of using the first residue of the thrA gene as residue 1. However, this results in placing the regulatory region of the thr operon at the opposite end of the 4.6-Mb sequence from the operon itself. [Researchers] therefore defined nucleotide 1 as the A residue 189 nucleotides upstream of the initiation codon for thrL, the first gene on the genetic map. [Researchers] did not detect any feature spanning this point.)"
Entered by Ron Milo - Admin
ID 100269