Probes H49 and JL8 define a pair of size-polymorphic homologous chromosomes. (A) Separation of T. cruzi chromosomal bands by PFGE and staining with ethidium bromide. The arabic and roman numerals indicate the sizes and numbers of the chromosomal bands, respectively. The insert shows the hybridization of probes H49 and JL8 with bands XVI and XVII. (B) The chromosomal bands XVI (2.3 Mb) and XVII (2.6 Mb) were isolated from a preparative PFGE gel and digested with EcoRI (E) or BamHI (B) restriction enzymes. The restriction fragments were separated by conventional agarose gel electrophoresis, blotted into a nylon membrane, and hybridized with probes H49 and JL8. (C) The chromosomal bands XVI and XVII were isolated from a preparative PFGE gel and digested withNotI and SfiI (N/S) or NotI (N). Restriction fragments were separated by PFGE (100 V, pulses of 10 sec to 120 sec, 40 hr) and hybridized with probes H49 and JL8.