GENETIC DIVERSITY AMONG LEISHMANIA (VIANNIA) PARASITES

The mode of reproduction in, and population structure of Leishmania (V iannia) parasites were deduced from the nature and extent of genetic v ariation in the parasites: Forty-seven zymodemes belonging to the Vian nia subgenus were analysed by enzyme electrophoresis and the profiles compared with those of two zymodemes belonging to the Leishmania subge nus. The results revealed extensive genetic variation in Viannia. The widespread occurrence of certain zymodemes, the level of heterozygosit y and the great similarity observed among the samples are indicative o f a clonal population structure. However, the large number of recurren t mutations needed to explain the variation observed and the presence of hybrid parasites indicate that occasional bouts of genetic exchange may occur.