a1 Department of Biology, King's College London, Campden Hill Road, London W8 7AH and Department of Palaeontology, The Natural History Museum, Cromwell Road, London SW7 5BD
a2 Department of Zoology, The Natural History Museum, Cromwell Road, London SW7 5BD
Partial 28S ribosomal RNA (rRNA) gene sequences, including the variable domains D1, D2 and D3, were determined for representative species from the 4 Schistosoma species groups. On an alignment of 1345 bp from S. mansoni, S. haematobium, S. spindale and S. japonicum (with Heterobilharzia americana chosen as an outgroup), both maximum likelihood and maximum parsimony analyses provide a robust molecular phytogeny for the genus; ((((S. haematobium, S. spindale), S. mansoni), S. japonicum), H. americana). When analysed separately, both domain D1 and domain D2 yielded similarly informative data whereas D3 failed to resolve the phylogeny. These results confirm a phylogeny previously suggested by 18S rRNA gene sequences, corroborating the status of S. spindale as a sister taxon to S. haematobium, and demonstrate the utility of 28S rRNA gene sequence data for resolving phylogenies within the Schistosomatidae.
Note: nucleotide sequence data reported in this paper are available in the EMBL database under the accession numbers Z46503/04/05/06/21.
(Received October 06 1994)
(Revised January 23 1995)
(Accepted January 23 1995)
* Reprint requests to D. A. Johnston, Department of Zoology, The Natural History Museum, Cromwell Road, London SW7 5BD.