DNA content and molecular karyotype of trypanosomes of the subgenus Nannomonas

The relative DNA contents of representative stocks of 5 groups within the trypanosome subgenus Nannomonas (Trypanosoma simiae, Godfreyi, T. congolense Savannah, Forest and Kilifi) were measured by flow cytometry. The range of DNA contents formed a continuum. Nevertheless small differences were observed between the groups, with T. simiae/T. congolense Savannah and T. congolense Kilifi/Forest at the lower and higher ends of the range respectively. Analysis of karyotype by pulsed field gel electrophoresis showed all the 5 Nannomonas groups to have minichromosomes and variable numbers of small chromosomes in the 100-700 kb size range. The size and relative number of mini-chromosomes varied from group to group, but no correlation between molecular karyotype and DNA content was observed.