Use of DNA hybridization values to construct three-dimensional models of fluorescent pseudomonad relationships

Three-dimensional models of the relationships among fluorescent pseudomonads were prepared from appropriately transformed percent DNA homology values. The transformation selected was f(x) = ( (1 - HOM/HOM)200, where HOM = fractional DNA homology and 200 is a scaling factor. Model accuracy was quite good as a plot of transformed DNA homology values versus model distances was essentially linear for homology values greater than 30%. The model suggested that bacterial strains within the fluorescent pseudomonads appear to be related in a three-dimensional continuum with no clear and easy "natural" demarcation into groups (i.e., species).