COMPARISON OF THE INTERGENIC SPACERS AND 3' END REGIONS OF THE LARGE SUBUNIT (28S) RIBOSOMAL-RNA GENE FROM 3 SPECIES OF SCHISTOSOMA

The sequences for the entire intergenic spacer (IGS) and 3' end region of the large subunit (28S) ribosomal RNA gene are presented for Schis tosoma intercalatum, S. haematobium and S. mansoni. The IGS was found to have at least 2 size formats for S. intercalatum and S. haematobium and the region for all 3 species contains numerous repeats and eviden ce of recombination. An A+T rich sequence found in S. intercalatum and S. haematobium is described and its possible function and origins are discussed. The amplification of this region by means of the polymeras e chain reaction can be used to discriminate clearly between the 3 spe cies involved in this study. The putative end of the 28S gene is ident ified.