Southern blot hybridization with homologous kDNA probes and corresponding autoradiographies. A) Agarose gel electrophoresis showing Hinf-I kDNA restriction profiles: M-DNA marker: λ Hind II/ox Hae III, 1-kDNA profile I, 2-kDNA profile II, 3-kDNA profile III, 4–5-T. cruzi populations after passage in immunosuppressed mice (kDNA profile II). B) autoradiography after hybridization with kDNA profile I used as probe. C) autoradiography after hybridization with kDNA profile III as probe. (D) autoradiography after probing with kDNA profile II.