Population structure of the social amoeba Dictyostelium rosarium based on rDNA

The extent of genetic variation that occurs among isolates of the social amoeba Dictyostelium rosarium obtained from a number of widely separated geographical localities around the world was investigated. Population diversity of D. rosarium was analyzed using sequences from the rDNA internal transcribed spacer (ITS1 and ITS2) and the 5.8S gene of 24 different isolates. Sequence analysis revealed little variation in the approximately 900 base pair ITS region of D. rosarium. No significant sequence variation was detected among the isolates examined, which suggests that the ITS region is extremely conserved in this species and also that D. rosarium morphotypes constitute a well-defined genetic entity (i.e., species).