ANALYSIS OF GENETIC DIVERSITY AT THE AROM LOCUS IN ISOLATES OF PNEUMOCYSTIS-CARINII

The DNA sequences of a portion of the 5-enolpyruvyl shikimate phosphat e synthase domain of the arom gene, encoding the pentafunctional AROM protein, were determined from isolates of Pneumocystis carinii from fi ve mammalian host species (rat, human, ferret, rabbit and mouse). High levels of genetic divergence were found among P. carinii derived from different hosts species, 7-22% at the DNA sequence level, and 7-26% a t the derived amino acid sequence level. Two separate and distinct seq uences were isolated from infected ferret lungs. Low levels of diverge nce were seen in human-derived organisms.