Nucleotide distribution in the dna of escherichia coli
Journal of Molecular Biology 49(3): 603-608
ISSN/ISBN: 0022-2836 PMID: 4916551 DOI: 10.1016/0022-2836(70)90284-6
Fragments of various lengths derived from the DNA of Escherichia coli were fractionated with respect to the buoyant density of their mercury complexes. Fragments 105 nucleotide pairs long proved to be uniform in density and composition (51% guanine plus cytosine) except for a small fraction ranging down to 49%. Fragments 1900 nucleotide pairs long varied between 39 and 56% guanine plus cytosine, with a standard deviation of ±3.8 per cent. The distribution was little affected by variation in length of fragments between 1200 and 2300 nucleotide pairs.