An endonuclease restriction analysis of the ribosomal RNA genes of Trypanosoma cruzi.

The location of ribosomal RNA genes in total-nuclear-enriched DNA preparations of Trypanosoma cruzi was analyzed by using restriction endonucleases and the eight cytoplasmic ribosomal RNA species of this organism. Two contiguous SstI DNA fragments of about 9.88 and 1.7 kilobase pairs contained the three large-size ribosomal RNA species, 18 S, beta, and alpha, and three small-size ribosomal RNA species, s1, s2 and s3. The other two small-size ribosomal species, s4 and s5, were located outside the ribosomal RNA cistron and independently of each other. Spacers of a presumed large length, about 20 kilobase pairs or more, hampered the identification of putative adjacent ribosomal RNA cistrons.