A DNA-FINGERPRINTING METHOD FOR INDIVIDUAL CHARACTERIZATION OF TOXOPLASMA-GONDII STRAINS - COMBINATION WITH ISOENZYMATIC CHARACTERS FOR DETERMINATION OF LINKAGE GROUPS

The genetic polymorphism of Toxoplasma gondii was evaluated for 14 str ains by isoenzyme and DNA analysis. The 14 strains belonged to 5 diffe rent zymodemes defined by the variable patterns of 6 enzyme systems. A restriction-fragment-length polymorphism analysis was carried out wit h two endonucleases (Sal I and Pst I) and two repetitive probes (TGR1E and TGR6). This kind of repetitive probe allowed an individual identi fication of strain, with 13 schizodemes being observed among 14 strain s. Only two strains were found to be totally identical when DNA and is oenzyme characters were considered. The numerical taxonomy methods app lied to the results obtained for both types of characters allowed dete rmination of linkage groups. Strain clustering obtained by numerical a nalysis of DNA characters alone is similar to the clustering obtained by analysis of isoenzyme and DNA characters together. A relationship w as observed between the defined groups and virulence in Swiss mice.