Current research is directed to an understanding of the mycoplasmas, small bacteria lacking a cell wall and representing the smallest free-living life form. I am studying the phylogeny of several of these organisms, as represented in 16S rRNA sequence comparisons. We are also determining a relatively high resolution physical/genetic map of Mycoplasma hyopneumoniae, a pathogen of swine, to compare that of M. flocculare, a closely related but nonpathogenic species.