Range of the molecular complexities of bacterial genomes within some Well-Established bacterial species

The genome sizes of a number of strains belonging to 5 different well-established bacterial species were determined in 8 to 45 replicate experiments by means of the initial renaturation rate method. Published data on 7 other bacterial species were also examined. It appears that the genome sizes of different strains within a single species are either identical or show no great differences. The average half range of the distribution is 10% of the average genome molecular weight and does not exceed 18%. Most species evidence one or two clusters of strains with identical genome size and a few strains differing distinctly as to their genome size.